BMCB 658 Lecture Notes - Lecture 17: Collision Frequency, Insulin, Thiamine Pyrophosphate
Document Summary
Stage 1: pyruvate from glycolysis is converted to acetyl-coa. Stage 2: tca cycle oxidation of acetyl-coa. Eukaryotes: glycolysis occurs in cytosol & taca in mitochondria. Reactions of tcac in matrix: the only exception is fad-linked reaction (embedded in inter- mitochondrial membrane) Oxidation by nad+ and formation of a thioester. Conversion requires nad+, fad, mg2+, thiamine pyrophosphate, coenzyme. Attached to enzyme by amide bond to amino group of lysine. Three directly involved in pyruvate acetyl-coa. Pdh kinase & pdh phosphatase are regulatory of whole complex. Three advantages to the complex: decrease distance, increase collision frequency, channeling: minimizing side reactions, coordinate regulatory control. Glycolysis isn"t like this because glycolysis is related to other pathways and some products need to be siphoned away to those other pathways. Product inhibition: nadh & acetyl-coa: compete with nad+ & coa binding sites, increase in nadh or acetyl-coa drives reactions backwards.