5052MBP12Y
Enzymes and Enzyme Inhibitors;
Basic concepts and Enzyme kinetics;
The substrate has gibbs or free energy, the energy in the product is more or less in
than in the substrate; less = energy became available/ was released → energy left
so can be spontaneous. Thermodynamics only looks at if a reaction can happen
spontaneously, kinetics look if this is really the case. Enzymes help reactions by
lowering the energy needed for the reaction to occur, it brings the enzyme to the
transition state. A prosthetic group is needed in enzymes, like iron.
There are different types of enzyme classes, oxido-reductase → transfers electrons
and or protons (oxidase, oxigenase, dehydrogenase and reductase). Transferase →
transfers phosphate groups (kinase). Hydrolase → perform hydrolyse reactions
where a group gets splitsed off (proteasen, nucleasen, fosfatasen and ATPasen).
Lysase (synthase) → Delete groups resulting in a double binding or create a new
ring structure (decarboxylase, adenylate cyclase, ATP-citrate lyase). Isomerase →
enzymen that move a group in a molecule like fosfoglucomutase (kan
glucose-1-fosfaat in 6 omzetten). Ligase (synthetase) → put two substrates
together using ATP-hydrolysis (pyruvate carboxylase).
Enzyme reaction has two steps, the interaction frome enzyme and substrate
(binding) and the katalyse. S+E → ES which is reversible and ES → EP and EP →
E+P which is not reversible. Affinity is high when S and E bind well, Km which is ½
Vmax. Turnover number, how many reactions happen per second, Kcat and
Vmax.
Single domain enzymes (michealis menten enzymes) show a hyperbolic curve.
Competitive inhibitors compete with the substrate for the same binding sites →
increased apparent Km and Vmax unchanged. Noncompetitive inhibitors bind at
allosteric site and change their structure of enzymes → decreased apparent Vmax
but Km unchanged. Inhibitors that bind irreversibely to enzymes → decreased
Vmax ; fewer active enzymen.
Allosteric enzymes are multidomain enzymes (single subunit with different
domains) or multisubunit enzymes (dimers, trimers etc). Allosteric inhibitors bind
allosteric enzymes reverisbely at an allosteric site and change the enzyme from a
more-active, relaxed state R, to a less- active, T state. Allosteric enzymes are
often regulatory and show a S curve.
Suicide inhibitors are modified substrates that modify active sites of an enzyme
which is irreversible like suicide. Like MOA.
,Cyctochrome P450 → CYP. A cyctochrome is a protein that transfers electrons,
using heme as its prosthetic group. 57 different CYP-enzymes in 18 families.
CYP2E1 is responsible for removing the xenobiotic ethanol from the body. They do
this by , they need oxygen and electrons. They break O2 in 2 O-, added to the
substrate and one is made until water. RH + O2 + NAPDH + H → ROH + H2O +
NADP+. CYP’s prosthetic group is heme, coenzyme is NADPH, substrate RH and
co-substrate O2.
Drug development:
Two approaches
Compound → physiological effect → molecular target, now it is molecular target →
compound → physiological effect. Alexander
Flemming discovered penicillin.
Penicillin looks a lot like ampicillin, ampicillin has an
amino group after the ring structure. The active
groups are the amide-groups that can form
amino-bonds. Enzymes recognize amide bonds and
bind to the drug.
- Penicillin inhibits crosslinking of peptido-glycan chains → cell wall of
bacteria weakens and cell lyses.
Sildefanil inhibits phosphodiesterase 5 which hydrolyses cGMP to GMP. cGMP
results in relaxation of smooth muscle cells, so this will result in relaxation of blood
vessels used in high blood pressure or angina pectoris. Side effect → erectie,
corpus cavernosum relaxes and allows for the inflow of blood, now sildenafil is
viagra.
HIV inhibitor is a cocktail, it affects multiple parts of the HIV-virus life cycle. The
AIDS medicine is multiple drugs. HIV protease consists of two identical subunits.
Cleaves multidomain viral proteins into their active forms, by inhibiting this HIV was
prevented to be infectious. Indinavir resembles the peptide substrate of the HIV
protease and is able to close the the protease off.
Influenza virus carries two surface proteins H and N, the virus targets the plasma
membrane of mammalian cells through the binding of H to sialic acids residues. At a
later stage N cleaves off the sialic acid residues to release the viral particle →
endocytosis. N is also responsible for the exocytosis by binding to sialic acid
residue and cleaving this off. Drug against influenza virus looks like the sialic acid
which binds N and inhibits it. Now the virus can enter the cell, but not exit so the
infection is slowed down.
,ADME properties of drugs, adsorption to the bloodstream, distribution throughout
the whole body so it can find its target, metabolism and
excretion.
- A, you would like it to be a small tablet introduced oral.
Lipinski rule of 5 determines its adsorption → LogP
makes sure it is soluble enough to be in the lumen of
the intestines and in the bloodstream, and hydrophobe
enough to pass the cell membrane. H-bond acceptors
are N and O.
- D, hydrophobic molecules bind to serum albumin in blood which leads to
lower distribution. Many compounds are unable to pass the blood-brain
barrier.
- M, xenobiotics are tried to be removed by the body. They are modified
through oxidation and conjugation. In result they become more water soluble
and more easily recognized as foreign compound. Oxidation (Phase I
transformation)of ibuprofen is carried out by P450 in the liver, making it more
water soluble and excreted more easily via urine. Conjugation (phase II
transformation) is the addition of gluthatione, glucuronic acid or sulfate.
This reduces the excretion and keeps it in the body longer.
- E, excretion is from intestine to blood, liver via bile to intestine or via urine.
The excretion has a half-life (t½).
There are different stages of drug development. From research institutes to
pharmaceutical companies to clinical trials.
IC50 is the inhibitory concentration at 50% concentration, Cmax is the maximal
concentration in the bloodstream. Efficacy is the number of patients who report
improvement. The power of the placebo effect should not be underestimated.
WG
Enzymes lower activation energy, so then the reaction could happen spontaneously.
Does this by orienting 2 substrates in such a way that is is easier for the reaction to
occur or -,- . Sucrase can do the opposite, but needs energy. Changes is Vmax =
changes in active site. Km = binding site. Molecular mechanism penicillin; enzym
DD-transpeptidase. Oxygenase altijd op substraat O toevoegen. What type of
inhibitor are the inhibitors?
Penicillin niet intacte celwand, leidt tot instroom van water door hoge concentratie
metabolieten in de bacterie dus door zoveel water zal het exploderen. Difference
gram positve gram negative, gram positive rely on their peptidoglycan. Mechanism
of enzyme must be involved with suicide inhibitors. Penultimate ones are replaced
with the enzyme and then a covalent bond between peptidoglycans happens. COX
→ cyclooxygenase you also have pox which are both in
prostaglandin H2 synthethase. Aspirin is an irreversible
, inhibitor, ibuprofen is reversible. Prostglandin H2 is een precursor voor 3
verschillende dingen, vandaar hebben aspirije en ibuprofen vele effecten.
Enzymes and Enzyme Inhibitors;
Basic concepts and Enzyme kinetics;
The substrate has gibbs or free energy, the energy in the product is more or less in
than in the substrate; less = energy became available/ was released → energy left
so can be spontaneous. Thermodynamics only looks at if a reaction can happen
spontaneously, kinetics look if this is really the case. Enzymes help reactions by
lowering the energy needed for the reaction to occur, it brings the enzyme to the
transition state. A prosthetic group is needed in enzymes, like iron.
There are different types of enzyme classes, oxido-reductase → transfers electrons
and or protons (oxidase, oxigenase, dehydrogenase and reductase). Transferase →
transfers phosphate groups (kinase). Hydrolase → perform hydrolyse reactions
where a group gets splitsed off (proteasen, nucleasen, fosfatasen and ATPasen).
Lysase (synthase) → Delete groups resulting in a double binding or create a new
ring structure (decarboxylase, adenylate cyclase, ATP-citrate lyase). Isomerase →
enzymen that move a group in a molecule like fosfoglucomutase (kan
glucose-1-fosfaat in 6 omzetten). Ligase (synthetase) → put two substrates
together using ATP-hydrolysis (pyruvate carboxylase).
Enzyme reaction has two steps, the interaction frome enzyme and substrate
(binding) and the katalyse. S+E → ES which is reversible and ES → EP and EP →
E+P which is not reversible. Affinity is high when S and E bind well, Km which is ½
Vmax. Turnover number, how many reactions happen per second, Kcat and
Vmax.
Single domain enzymes (michealis menten enzymes) show a hyperbolic curve.
Competitive inhibitors compete with the substrate for the same binding sites →
increased apparent Km and Vmax unchanged. Noncompetitive inhibitors bind at
allosteric site and change their structure of enzymes → decreased apparent Vmax
but Km unchanged. Inhibitors that bind irreversibely to enzymes → decreased
Vmax ; fewer active enzymen.
Allosteric enzymes are multidomain enzymes (single subunit with different
domains) or multisubunit enzymes (dimers, trimers etc). Allosteric inhibitors bind
allosteric enzymes reverisbely at an allosteric site and change the enzyme from a
more-active, relaxed state R, to a less- active, T state. Allosteric enzymes are
often regulatory and show a S curve.
Suicide inhibitors are modified substrates that modify active sites of an enzyme
which is irreversible like suicide. Like MOA.
,Cyctochrome P450 → CYP. A cyctochrome is a protein that transfers electrons,
using heme as its prosthetic group. 57 different CYP-enzymes in 18 families.
CYP2E1 is responsible for removing the xenobiotic ethanol from the body. They do
this by , they need oxygen and electrons. They break O2 in 2 O-, added to the
substrate and one is made until water. RH + O2 + NAPDH + H → ROH + H2O +
NADP+. CYP’s prosthetic group is heme, coenzyme is NADPH, substrate RH and
co-substrate O2.
Drug development:
Two approaches
Compound → physiological effect → molecular target, now it is molecular target →
compound → physiological effect. Alexander
Flemming discovered penicillin.
Penicillin looks a lot like ampicillin, ampicillin has an
amino group after the ring structure. The active
groups are the amide-groups that can form
amino-bonds. Enzymes recognize amide bonds and
bind to the drug.
- Penicillin inhibits crosslinking of peptido-glycan chains → cell wall of
bacteria weakens and cell lyses.
Sildefanil inhibits phosphodiesterase 5 which hydrolyses cGMP to GMP. cGMP
results in relaxation of smooth muscle cells, so this will result in relaxation of blood
vessels used in high blood pressure or angina pectoris. Side effect → erectie,
corpus cavernosum relaxes and allows for the inflow of blood, now sildenafil is
viagra.
HIV inhibitor is a cocktail, it affects multiple parts of the HIV-virus life cycle. The
AIDS medicine is multiple drugs. HIV protease consists of two identical subunits.
Cleaves multidomain viral proteins into their active forms, by inhibiting this HIV was
prevented to be infectious. Indinavir resembles the peptide substrate of the HIV
protease and is able to close the the protease off.
Influenza virus carries two surface proteins H and N, the virus targets the plasma
membrane of mammalian cells through the binding of H to sialic acids residues. At a
later stage N cleaves off the sialic acid residues to release the viral particle →
endocytosis. N is also responsible for the exocytosis by binding to sialic acid
residue and cleaving this off. Drug against influenza virus looks like the sialic acid
which binds N and inhibits it. Now the virus can enter the cell, but not exit so the
infection is slowed down.
,ADME properties of drugs, adsorption to the bloodstream, distribution throughout
the whole body so it can find its target, metabolism and
excretion.
- A, you would like it to be a small tablet introduced oral.
Lipinski rule of 5 determines its adsorption → LogP
makes sure it is soluble enough to be in the lumen of
the intestines and in the bloodstream, and hydrophobe
enough to pass the cell membrane. H-bond acceptors
are N and O.
- D, hydrophobic molecules bind to serum albumin in blood which leads to
lower distribution. Many compounds are unable to pass the blood-brain
barrier.
- M, xenobiotics are tried to be removed by the body. They are modified
through oxidation and conjugation. In result they become more water soluble
and more easily recognized as foreign compound. Oxidation (Phase I
transformation)of ibuprofen is carried out by P450 in the liver, making it more
water soluble and excreted more easily via urine. Conjugation (phase II
transformation) is the addition of gluthatione, glucuronic acid or sulfate.
This reduces the excretion and keeps it in the body longer.
- E, excretion is from intestine to blood, liver via bile to intestine or via urine.
The excretion has a half-life (t½).
There are different stages of drug development. From research institutes to
pharmaceutical companies to clinical trials.
IC50 is the inhibitory concentration at 50% concentration, Cmax is the maximal
concentration in the bloodstream. Efficacy is the number of patients who report
improvement. The power of the placebo effect should not be underestimated.
WG
Enzymes lower activation energy, so then the reaction could happen spontaneously.
Does this by orienting 2 substrates in such a way that is is easier for the reaction to
occur or -,- . Sucrase can do the opposite, but needs energy. Changes is Vmax =
changes in active site. Km = binding site. Molecular mechanism penicillin; enzym
DD-transpeptidase. Oxygenase altijd op substraat O toevoegen. What type of
inhibitor are the inhibitors?
Penicillin niet intacte celwand, leidt tot instroom van water door hoge concentratie
metabolieten in de bacterie dus door zoveel water zal het exploderen. Difference
gram positve gram negative, gram positive rely on their peptidoglycan. Mechanism
of enzyme must be involved with suicide inhibitors. Penultimate ones are replaced
with the enzyme and then a covalent bond between peptidoglycans happens. COX
→ cyclooxygenase you also have pox which are both in
prostaglandin H2 synthethase. Aspirin is an irreversible
, inhibitor, ibuprofen is reversible. Prostglandin H2 is een precursor voor 3
verschillende dingen, vandaar hebben aspirije en ibuprofen vele effecten.
