Metabolisme Heme dan Globin

1. Metabolisme Heme dan Globin dr. Erdiana

2. Hemoglobin • terdiri dari • heme (porfirin yang mengikat zat besi) dan • ferroporfirin • rantai polipeptida globin (alfa,beta,gama, dan delta

3. Struktur Hemoglobin • 4 molekul protein • 4 heme • HbA (2 alpha-globulin chains dan 2 beta-globulin chains) • HbF (2 alpha & 2 gamma) • HbA2 (2 alpha & 2 delta)

4. 141 molekul asama amino pada rantai alfa • 146 mol asam amino pada rantai beta, gama dan delta

6. Heme Synthesis • Heme is synthesized in a complex series of steps involving enzymes in the mitochondrion and in the cytosol of the cell • The first step in heme synthesis takes place in the mitochondrion, with the condensation of succinyl CoA and glycine by ALA synthase to form 5-aminolevulic acid (ALA)

7. This molecule is transported to the cytosol where a series of reactions produce a ring structure called coproporphyrinogen III • This molecule returns to the mitochondrion where an addition reaction produces protoporhyrin IX • The enzyme ferrochelatase inserts iron into the ring structure of protoporphyrin IX to produce heme

8. Heme Biosynthesis. The sythesis of heme is a complex process that involves multiple enzymatic steps. The process begins in the mitochondrion with the condensation of succinyl-CoA and glycine to form 5-aminolevulinic acid. A series of steps in the cytoplasm produce coproporphrynogen III, which re-enters the mitochondrion. The final enzymatic steps produce heme.

10. Globin Synthesis • Two distinct globin chains (each with its individual heme molecule) combine to form hemoglobin • One of the chains is designated alpha. The second chain is called "non-alpha".

12. 2 Suksinil-KoA + 2 Glisin membentuk senyawa Pirol • 4 Pirol akan membentuk senyawa Protoporfirin IX • Protoporfirin IX + Fe2+ membentuk senyawa Heme • 4 Hem + Polipeptida membentuk Rantai Hemoglobin (α atau β) • Rantai 2α + Rantai 2β membentuk hemoglobin A

17. sekian