BIOCHEMIE VAN DE HUISDIEREN II
INHOUDSOPGAVE
Hoofdstuk 17; vetzuursynthese ........................................................................................................................ 4
Inleiding ............................................................................................................................................................... 4
Vetzuursynthese ............................................................................................................................................. 4
Algemene kenmerken biosynthese van vetzuren ........................................................................................... 4
Voorbereidende fase ........................................................................................................................................... 5
Algemeen ........................................................................................................................................................ 5
Vetzuursynthese .................................................................................................................................................. 5
Energetische balans ........................................................................................................................................ 6
Transmembranair transport ................................................................................................................................ 6
Acetyl-CoA ....................................................................................................................................................... 7
NADPH ............................................................................................................................................................. 8
Algemeen ........................................................................................................................................................ 8
Verschil NADH & NADPH ................................................................................................................................. 9
Regulatie ......................................................................................................................................................... 9
Hoofdstuk 18: stikstofexcretie ....................................................................................................................... 10
Inleiding ............................................................................................................................................................. 10
Verwerking aminogroepen ................................................................................................................................ 10
Aminozuurafbraak in lever ............................................................................................................................ 11
Transportsystemen voor aminogroepen vanuit andere weefsels ................................................................ 13
Ureumcyclus ...................................................................................................................................................... 14
Energetische kost .............................................................................................................................................. 15
Regulatie ........................................................................................................................................................... 15
Verwerking koolstofskelet ................................................................................................................................. 16
Biosynthese van aminozuren............................................................................................................................. 16
Hoofdstuk 19: signaaltransductie ................................................................................................................... 17
Inleiding ............................................................................................................................................................. 17
Algemene eigenschappen van signaaltransducersystemen ......................................................................... 17
Basismechanismen voor signaaltransductie ................................................................................................. 17
Ionkanalen......................................................................................................................................................... 18
Algemeen ...................................................................................................................................................... 18
Receptorenzymen .............................................................................................................................................. 18
Algemeen ...................................................................................................................................................... 18
Insuline .......................................................................................................................................................... 19
cGMP als second messenger ......................................................................................................................... 20
Receptoren zonder intrinsieke enzymactiviteit ................................................................................................. 21
JAK-STAT-mechanisme .................................................................................................................................. 21
G-proteïne-gekoppelde receptoren ................................................................................................................... 22
Drie essentiële elementen ............................................................................................................................ 22
Adrenerge receptorsystemen (adrenoreceptoren) ...................................................................................... 22
1
, Nucelaire receptoren ......................................................................................................................................... 23
Voorbeeld; zicht................................................................................................................................................. 24
Transmembranaire electrische potentiaal (Vm) door: .................................................................................. 24
Amplificatie van het signaal .......................................................................................................................... 24
Beëindiging van het signaal ........................................................................................................................... 25
Calcium .......................................................................................................................................................... 25
Kleurenzicht .................................................................................................................................................. 26
Samenvatting GPKR ....................................................................................................................................... 26
Hoofdstuk 20: hormonen ............................................................................................................................... 27
Classificatie........................................................................................................................................................ 27
Verschil tussen neurotransmitter & hormoon? ............................................................................................ 27
Peptidehormonen .............................................................................................................................................. 28
Insuline .......................................................................................................................................................... 28
Neuropeptiden .............................................................................................................................................. 28
Aminozuurderivaten .......................................................................................................................................... 30
Schildklierhormonen ..................................................................................................................................... 30
Eicosanoïden ..................................................................................................................................................... 32
eigenschappen .............................................................................................................................................. 32
Prostaglandinen ............................................................................................................................................ 32
Leukotriënen: lineaire pathway .................................................................................................................... 33
Steroïden ........................................................................................................................................................... 34
Classificatie .................................................................................................................................................... 34
Synthese ........................................................................................................................................................ 35
Secosteroïden .................................................................................................................................................... 35
Vitamine D2: ergocalciferol ........................................................................................................................... 35
Hoofdstuk 21: neurotransmitters ................................................................................................................... 36
Ionkanalen......................................................................................................................................................... 36
Voltage gated Na2+ channels ........................................................................................................................ 36
Typevoorbeeld ligand gated ion channel: acetylcholinereceptor ................................................................. 37
Cholinerge neurotransmissie: acetylcholine ...................................................................................................... 37
Choline acetyltransferase .............................................................................................................................. 37
Afbraak: acetylcholinesterase ....................................................................................................................... 38
Acetylcholinereceptoren ............................................................................................................................... 38
Catecholamines ................................................................................................................................................. 38
Synthesevolgorde .......................................................................................................................................... 38
Als geneesmiddel/ drug ................................................................................................................................ 38
Synthese ........................................................................................................................................................ 38
Afbraak .......................................................................................................................................................... 38
Hoofdstuk 22: metabolisme van de lever ....................................................................................................... 39
Inleiding ............................................................................................................................................................. 39
De lever ............................................................................................................................................................. 39
Hoofdstuk 23: metabolisme van het vetweefsel ............................................................................................ 49
Inleiding ............................................................................................................................................................. 49
Functie vetweefsel ........................................................................................................................................ 49
Glucose-glycerolcyclus....................................................................................................................................... 49
Gglycerol-3-fosfaat ........................................................................................................................................ 49
2
, verloop .......................................................................................................................................................... 50
Triacylglycerolcyclus .......................................................................................................................................... 51
Vlak na maaltijd ............................................................................................................................................. 51
Tussen 2 maaltijden ...................................................................................................................................... 51
Vasten ........................................................................................................................................................... 52
Diabetes ........................................................................................................................................................ 52
Regulatie ........................................................................................................................................................... 53
Insulinetoestand............................................................................................................................................ 53
Glucagon situatie .......................................................................................................................................... 54
Algemeen ...................................................................................................................................................... 54
Globaal metabolisme ..................................................................................................................................... 55
Spier .................................................................................................................................................................. 55
Fosfocreatine ................................................................................................................................................ 55
Cori Cyclus ..................................................................................................................................................... 55
Hersenen ........................................................................................................................................................... 56
Pancreas ............................................................................................................................................................ 56
Mechanisme .................................................................................................................................................. 56
Secretie ......................................................................................................................................................... 56
Globaal metabolisme ........................................................................................................................................ 57
insulineactiviteit ............................................................................................................................................ 57
Glucagonactiviteit ......................................................................................................................................... 57
Algemeen ...................................................................................................................................................... 57
Algemeen ...................................................................................................................................................... 58
Postprandiaal .................................................................................................................................................... 59
Algemeen ...................................................................................................................................................... 60
Interprandiaal ................................................................................................................................................... 61
Algemeen ...................................................................................................................................................... 61
Vasten ............................................................................................................................................................... 62
Regulatie lichaamsmassa .................................................................................................................................. 63
Lipostat-theorie ............................................................................................................................................. 63
Leptine experimenten ................................................................................................................................... 63
Tweede reeks experimenten......................................................................................................................... 63
Obesitas......................................................................................................................................................... 64
Insulineresistentie ......................................................................................................................................... 64
3
, HOOFDSTUK 17; VETZUURSYNTHESE
INLEIDING
- Cellulair functie van lipiden
o Opslag triacylglycerolen
o Structurele componenten van membranen
o Gespecialiseerde lipiden (pigmenten, hormonen)
- Primaire componenten; vetzuren
VETZUURSYNTHESE
- Strategie om wateronoplosbare vetzuren te produceren op basis van wateroplosbare precursoren
- Verhoudt zich conceptueel tov vetzuuroxidatie zoals glycolyse tov gluconeogenese, maar in praktijk
niet
- Gaat door in 2 verschillende compartimenten & maakt gebruik van totaal verschillende enzymen &
zelfs cofactoren. Het zijn dus niet elkaars omgekeerden.
- Conceptueel wel gelijkenissen: bij bèta-oxidatie telkens -2C per cyclus, bij synthese +2C per cyclus
ALGEMENE KENMERKEN BIOSYNTHESE VAN VETZUREN
- Endergonisch
- Reductief
- ATP als metabole energiebron
- NADPH als reductant
o Afkomstig van ppp, die ook plaatsvindt in cytosol.
- Vindt plaats in cytosol (bèta-oxidatie in mitochondriën)
4
INHOUDSOPGAVE
Hoofdstuk 17; vetzuursynthese ........................................................................................................................ 4
Inleiding ............................................................................................................................................................... 4
Vetzuursynthese ............................................................................................................................................. 4
Algemene kenmerken biosynthese van vetzuren ........................................................................................... 4
Voorbereidende fase ........................................................................................................................................... 5
Algemeen ........................................................................................................................................................ 5
Vetzuursynthese .................................................................................................................................................. 5
Energetische balans ........................................................................................................................................ 6
Transmembranair transport ................................................................................................................................ 6
Acetyl-CoA ....................................................................................................................................................... 7
NADPH ............................................................................................................................................................. 8
Algemeen ........................................................................................................................................................ 8
Verschil NADH & NADPH ................................................................................................................................. 9
Regulatie ......................................................................................................................................................... 9
Hoofdstuk 18: stikstofexcretie ....................................................................................................................... 10
Inleiding ............................................................................................................................................................. 10
Verwerking aminogroepen ................................................................................................................................ 10
Aminozuurafbraak in lever ............................................................................................................................ 11
Transportsystemen voor aminogroepen vanuit andere weefsels ................................................................ 13
Ureumcyclus ...................................................................................................................................................... 14
Energetische kost .............................................................................................................................................. 15
Regulatie ........................................................................................................................................................... 15
Verwerking koolstofskelet ................................................................................................................................. 16
Biosynthese van aminozuren............................................................................................................................. 16
Hoofdstuk 19: signaaltransductie ................................................................................................................... 17
Inleiding ............................................................................................................................................................. 17
Algemene eigenschappen van signaaltransducersystemen ......................................................................... 17
Basismechanismen voor signaaltransductie ................................................................................................. 17
Ionkanalen......................................................................................................................................................... 18
Algemeen ...................................................................................................................................................... 18
Receptorenzymen .............................................................................................................................................. 18
Algemeen ...................................................................................................................................................... 18
Insuline .......................................................................................................................................................... 19
cGMP als second messenger ......................................................................................................................... 20
Receptoren zonder intrinsieke enzymactiviteit ................................................................................................. 21
JAK-STAT-mechanisme .................................................................................................................................. 21
G-proteïne-gekoppelde receptoren ................................................................................................................... 22
Drie essentiële elementen ............................................................................................................................ 22
Adrenerge receptorsystemen (adrenoreceptoren) ...................................................................................... 22
1
, Nucelaire receptoren ......................................................................................................................................... 23
Voorbeeld; zicht................................................................................................................................................. 24
Transmembranaire electrische potentiaal (Vm) door: .................................................................................. 24
Amplificatie van het signaal .......................................................................................................................... 24
Beëindiging van het signaal ........................................................................................................................... 25
Calcium .......................................................................................................................................................... 25
Kleurenzicht .................................................................................................................................................. 26
Samenvatting GPKR ....................................................................................................................................... 26
Hoofdstuk 20: hormonen ............................................................................................................................... 27
Classificatie........................................................................................................................................................ 27
Verschil tussen neurotransmitter & hormoon? ............................................................................................ 27
Peptidehormonen .............................................................................................................................................. 28
Insuline .......................................................................................................................................................... 28
Neuropeptiden .............................................................................................................................................. 28
Aminozuurderivaten .......................................................................................................................................... 30
Schildklierhormonen ..................................................................................................................................... 30
Eicosanoïden ..................................................................................................................................................... 32
eigenschappen .............................................................................................................................................. 32
Prostaglandinen ............................................................................................................................................ 32
Leukotriënen: lineaire pathway .................................................................................................................... 33
Steroïden ........................................................................................................................................................... 34
Classificatie .................................................................................................................................................... 34
Synthese ........................................................................................................................................................ 35
Secosteroïden .................................................................................................................................................... 35
Vitamine D2: ergocalciferol ........................................................................................................................... 35
Hoofdstuk 21: neurotransmitters ................................................................................................................... 36
Ionkanalen......................................................................................................................................................... 36
Voltage gated Na2+ channels ........................................................................................................................ 36
Typevoorbeeld ligand gated ion channel: acetylcholinereceptor ................................................................. 37
Cholinerge neurotransmissie: acetylcholine ...................................................................................................... 37
Choline acetyltransferase .............................................................................................................................. 37
Afbraak: acetylcholinesterase ....................................................................................................................... 38
Acetylcholinereceptoren ............................................................................................................................... 38
Catecholamines ................................................................................................................................................. 38
Synthesevolgorde .......................................................................................................................................... 38
Als geneesmiddel/ drug ................................................................................................................................ 38
Synthese ........................................................................................................................................................ 38
Afbraak .......................................................................................................................................................... 38
Hoofdstuk 22: metabolisme van de lever ....................................................................................................... 39
Inleiding ............................................................................................................................................................. 39
De lever ............................................................................................................................................................. 39
Hoofdstuk 23: metabolisme van het vetweefsel ............................................................................................ 49
Inleiding ............................................................................................................................................................. 49
Functie vetweefsel ........................................................................................................................................ 49
Glucose-glycerolcyclus....................................................................................................................................... 49
Gglycerol-3-fosfaat ........................................................................................................................................ 49
2
, verloop .......................................................................................................................................................... 50
Triacylglycerolcyclus .......................................................................................................................................... 51
Vlak na maaltijd ............................................................................................................................................. 51
Tussen 2 maaltijden ...................................................................................................................................... 51
Vasten ........................................................................................................................................................... 52
Diabetes ........................................................................................................................................................ 52
Regulatie ........................................................................................................................................................... 53
Insulinetoestand............................................................................................................................................ 53
Glucagon situatie .......................................................................................................................................... 54
Algemeen ...................................................................................................................................................... 54
Globaal metabolisme ..................................................................................................................................... 55
Spier .................................................................................................................................................................. 55
Fosfocreatine ................................................................................................................................................ 55
Cori Cyclus ..................................................................................................................................................... 55
Hersenen ........................................................................................................................................................... 56
Pancreas ............................................................................................................................................................ 56
Mechanisme .................................................................................................................................................. 56
Secretie ......................................................................................................................................................... 56
Globaal metabolisme ........................................................................................................................................ 57
insulineactiviteit ............................................................................................................................................ 57
Glucagonactiviteit ......................................................................................................................................... 57
Algemeen ...................................................................................................................................................... 57
Algemeen ...................................................................................................................................................... 58
Postprandiaal .................................................................................................................................................... 59
Algemeen ...................................................................................................................................................... 60
Interprandiaal ................................................................................................................................................... 61
Algemeen ...................................................................................................................................................... 61
Vasten ............................................................................................................................................................... 62
Regulatie lichaamsmassa .................................................................................................................................. 63
Lipostat-theorie ............................................................................................................................................. 63
Leptine experimenten ................................................................................................................................... 63
Tweede reeks experimenten......................................................................................................................... 63
Obesitas......................................................................................................................................................... 64
Insulineresistentie ......................................................................................................................................... 64
3
, HOOFDSTUK 17; VETZUURSYNTHESE
INLEIDING
- Cellulair functie van lipiden
o Opslag triacylglycerolen
o Structurele componenten van membranen
o Gespecialiseerde lipiden (pigmenten, hormonen)
- Primaire componenten; vetzuren
VETZUURSYNTHESE
- Strategie om wateronoplosbare vetzuren te produceren op basis van wateroplosbare precursoren
- Verhoudt zich conceptueel tov vetzuuroxidatie zoals glycolyse tov gluconeogenese, maar in praktijk
niet
- Gaat door in 2 verschillende compartimenten & maakt gebruik van totaal verschillende enzymen &
zelfs cofactoren. Het zijn dus niet elkaars omgekeerden.
- Conceptueel wel gelijkenissen: bij bèta-oxidatie telkens -2C per cyclus, bij synthese +2C per cyclus
ALGEMENE KENMERKEN BIOSYNTHESE VAN VETZUREN
- Endergonisch
- Reductief
- ATP als metabole energiebron
- NADPH als reductant
o Afkomstig van ppp, die ook plaatsvindt in cytosol.
- Vindt plaats in cytosol (bèta-oxidatie in mitochondriën)
4
