Acetyl CoA metabolism

Acetyl-CoA metabolized through the TCA cycle yields 3 NADH, 1 FADH2, and 1 GTP—a total of 12 ATP equivalents (3 from each NADH, 2 from each FADH2, and 1 GTP—12 in all). Four O s are used, 1 for each NADH and FADH2. The P in this case is 10 (12 — 2 for the activation of acetate to acetyl-CoA). The P/O = 10/4 = 2.5. P/O ratios for anything else are calculated in the same way. 

If [14C]acetate (or [14C]acetyl-CoA) were injected into an animal, would radioactive carbons be found in glucose Explain your answer in terms of acetyl-CoA metabolism. 

Enzymatic regulation of liver acetyl-CoA metabolism in relation to ketogenesis, O. Wieland, L. Weiss, and I. Eger-Neufeldt, 1964, Adv. Enzyme Reg., 8599. 

They are converted back to acyl CoAs by carnitine acyltransferases appropriate for their chain length and enter the normal pathways for p-oxidation and acetyl CoA metabolism. The electrons from NADH and acetyl CoA can also pass from the peroxisome to the cytosol. The export of NADH-containing electrons occurs through use of a shuttle system similar to those described for NADH electron transfer into the mitochondria. 

Fatty acids and alcohols are products of yeast metabolism but the uncatalysed rate of chemical reaction between these substances is 1000 times too slow to account for ester formation in fermentation. Pantothenic acid (a precursor of coenzyme A) stimulates ester production [79] and factors which influence acetyl CoA metabolism affect ethyl acetate synthes s [77]. The biosynthesis of esters in yeast was therefore proposed to occur by the alcoholysis of acyl CoA compounds [77]. The alcohols involved in these reactions are ethanol and the fusel alcohols. The acyl CoA molecules used may be derived in one of several ways ... 

Disturbances in Acetyl-CoA Metabolism A Key Factor in Preclinical and Overt Thiamine Deficiency Encephalopathy... 

Bizon-Zygmahska, D., Jankowska-Kulawy, A., Bielarczyk, H., Pawelczyk, T., Ronowska, A., Marszall, M., and Szutowicz, A., 2011. Acetyl-CoA metabolism in amprolium-evoked thiamine pyrophosphate deficits in cholinergic SN56 neuroblastoma cells. Neurochemistry International. 59 208-216. 

Kocharin K, ChenY, SiewersV, Nielsen J. Engineering of acetyl-CoA metabolism for the improved production of polyhydroxybutyrate in Saccharomyces cerevisiae. Amb Express 2012 2 1-11. 

Acetyl-CoA synthetase (ACS) catalyzes the conversion of acetate to acetyl-CoA. In photosynthetic tissue, this enzyme is localized in the chloroplast (l) where it potentially provides a key source of acetyl-CoA for fatty acid, isoprenoid, and branch-chain amino acid biosynthesis. Acetyl-CoA synthetase s contribution to chloroplast acetyl-CoA is presently controversial because of the identification of alternative sources of acetyl-CoA (i. e. pyruvate dehydrogenase complex (2,3), and carnitine acyltransferase (4)), in the chloroplast. To further elucidate the role of ACS in chloroplast acetyl-CoA metabolism we have partially purified and characterized ACS from mature spinach leaves. 

Chen, Y., Daviet, L., Schalk, M., Siewers, V., Nielsen, J., 2013. Establishing a platform cell factory through engineering of yeast acetyl-CoA metabolism. Metabolic Engineering 15,48-54. 

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