BIOC 311 Final: review_document_final

• School: McGill University
• Department: Biochemistry
• Course: BIOC 311
• Professor: Julie St- Pierre

Document Summary

Recall: carboxymethyl group of pro-s-arm of citrate comes from acetyl-coa. C4 of oxaloacetate: pro-r arm of citrate, released as co2 in alpha-ketoglutarate dehydrogenase reaction in 1st turn of cac. Carboxyl carbon of acetate unit: 1st turn: half pool ends up in c1 of succinate (symmetric molecule), other half in c4, 2nd turn: loose half pool at step3 of cac and other half lost at step 4. Regulated by ratios: atp/adp, nadh/nad+, acetyl-coa/coash, succinyl- Coa/coash: when high: large energy charge, cac downregulated, when low: cac up-regulated (cells require energy production) Key enzymes outside cac: pyruvate dehydrogenase: decarboxylation of pyruvate to obtain acetyl- Molecule of oa must enter cac for each molecules of cac intermediate used in biosynthesis (replenishing intermediates) Activated by acetyl-coa: pairing of pyruvate between decarboxylation (acetyl-coa) or carboxylation (oa) based on (1) oxidation for atp generation or (2) conversion to starting materials for biosynthesis. Pyruvate is most important branch point in metabolism based on carbohydrates.