HEME SYNTHESIS EXAM LATEST UPDATED
Heme - ANSWER Is a metalloporphyrin. Has four pyrrole rings that are
linked to each other via methenyl bridges. Then four nitrogens of the
pyrrole ring bind ferrous iron in heme. If ferric iron is bound, then hemin
is formed.
Porphyrias - ANSWER Greek for purple pigment. Defects in the
synthesis of heme lead to the accumulation of intermediates of heme
synthesis in blood, tissues and urine. Can lead to red or dark urine,
reddish-brown teeth, ulcers that mutilate the nose, erratic behaviour and
severe photosensitivity, and facial hair. Severe cases have werewolf
features.
Bone marrow and liver - ANSWER Major tissues for heme synthesis.
Heme - ANSWER Needed in large quantities for hemoglobin and
myoglobin. Can act as a prosthetic group for specific enzymes like
cytochromes P450, cytochromes of the ETC, catalase or nitric oxide
synthase.
Lead - ANSWER Can severely inhibit heme synthesis due to interaction
with the zinc cofactor of two enzymes.
Vitamin B6 - ANSWER Needed for formation of pyridoxal phosphate.
PLP is needed as coenzyme for the first enzyme of heme synthesis.
Deficiency leads to anemia.
Heme synthesis in erythroid cells - ANSWER Is connected to protein
synthesis of globin chain. Accumulation of heme will lead to more globin
chain synthesis. (RBCs late on need large amounts of hemoglobin).
Synthesis of heme in erythroid cells in under control of erythropoeitin
and the availability of iron.
Heme - ANSWER Is a metalloporphyrin. Has four pyrrole rings that are
linked to each other via methenyl bridges. Then four nitrogens of the
pyrrole ring bind ferrous iron in heme. If ferric iron is bound, then hemin
is formed.
Porphyrias - ANSWER Greek for purple pigment. Defects in the
synthesis of heme lead to the accumulation of intermediates of heme
synthesis in blood, tissues and urine. Can lead to red or dark urine,
reddish-brown teeth, ulcers that mutilate the nose, erratic behaviour and
severe photosensitivity, and facial hair. Severe cases have werewolf
features.
Bone marrow and liver - ANSWER Major tissues for heme synthesis.
Heme - ANSWER Needed in large quantities for hemoglobin and
myoglobin. Can act as a prosthetic group for specific enzymes like
cytochromes P450, cytochromes of the ETC, catalase or nitric oxide
synthase.
Lead - ANSWER Can severely inhibit heme synthesis due to interaction
with the zinc cofactor of two enzymes.
Vitamin B6 - ANSWER Needed for formation of pyridoxal phosphate.
PLP is needed as coenzyme for the first enzyme of heme synthesis.
Deficiency leads to anemia.
Heme synthesis in erythroid cells - ANSWER Is connected to protein
synthesis of globin chain. Accumulation of heme will lead to more globin
chain synthesis. (RBCs late on need large amounts of hemoglobin).
Synthesis of heme in erythroid cells in under control of erythropoeitin
and the availability of iron.
