Rapoport Libering Cycle | Lecture Note

University:
Liberty University
Course:
BIOM 500 | Introduction to Biomedical Sciences
Academic year:

2024
Views:

107

Pages:

5
Author:

Sheha A.

Rapoport-Luebering cycle: It is a side reaction of the glycolytic pathway occurring in erythrocytes. Kinase reaction of glycolysis is bypassed in the erythrocytes. No energy is trapped from 2,3-bisphosphoglycerate (2,3-BPG). 2,3-BPG when combines with Hb reduces the affinity of Hb towards oxygen. In presence of 2,3-BPG, oxyhaemoglobin can unload oxygen more easily in tissue. In hexokinase deficiency, phosphorylation does not take place, so 2,3-BPG decreases. Thus, affinity to Hb increases. Pyruvate Dehydrogenase (PDH) Reaction: Pyruvate is oxidatively decarboxylated to acetyl CoA by pyruvate dehydrogenase enzyme complex. Acetyl CoA enters into the TCA cycle. Pyruvate Dehydrogenase Pyruvate -----> Acetyl CoA | | COASH FAD, TPP | CO2 | | NAD+ Lipoic acid NADH + H+ Inhibitors of TCA cycle: Aconitase enzyme is inhibited by fluoroacetate. α-ketoglutarate dehydrogenase is inhibited by arsenate. Succinate dehydrogenase is inhibited by malonate.