KIN217 Chapter Notes - Chapter 18: Dihydrolipoyl Transacetylase, Pyruvate Dehydrogenase, Acetyl-Coa
16 Aug 2017
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Pyruvate dehydrogenase forms acetyl coenzyme from a pyruvate: glycolysis occurs in cyto and tca occurs in mito, pyruvate must be transported. In mito matrix, pyruvate oxi decarboxylated by pyruvate dehydrog complex to form acetyl coa. Pyruvate combines w/ionized form of tpp and decarboxylated to yield hydroxyethyl-tpp cata by pyruvate dehydrogenase component (e1: oxidation. Hydroxyethyl group attached to tpp oxi to form acetyl group while simultaneously transferred to lipoamide, forming energy rich thioester bond. Disulfide group of lipoamide red to disulfhydryl cata by e1, yield acetyllipoamide: formation of acetyl coa. Thioester bond preserved as acetyl group transferred to coa: pyruvate deh(cid:455)drog co(cid:373)ple(cid:454) (cid:373)ust (cid:862)reset(cid:863) lipoa(cid:373)ide so co(cid:373)plex can cata another rxn, 4th step, oxi form of lipoamide regen by dihydrolipoyl dehydrog (e3) Lipoamide can move between different active sites: pyruvate is decarboxylated at active site of e1, form hydroxyethyl-tpp, and co2 leaves.
