Extracts from human platelets contain the enzymes of de novo fatty acid biosynthesis. The pattern of incorporation of acetate-1-(14)C into fatty acids by intact platelets indicates that these enzymes function in platelets. The level of acetyl-coenzyme A (CoA) carboxylase activity in extracts of platelets from normal subjects is 0.036 +/-0.01 mmumole of malonyl-CoA formed per min per mg of prote...

The rate of fatty acid synthesis in hepatocytes from meal-fed rats was manipulated over a wide range using glucose, lactate, and pyruvate to drive the system maximally, and glucagon, 5-(tetradecyloxy)-2-furoic acid (RMI 14,514), or a combination of both agents to inhibit lipogenesis. Measurements were made of cellular malonyl-CoA levels, long chain acylcarnitine concentration, and [l-‘4C]oleate...

Malonyl-CoA decarboxylase (MCD) catalyzes the degradation of malonyl-CoA, an important modulator of fatty acid oxidation. We hypothesized that increased fatty acid availability would increase the expression and activity of heart and skeletal muscle MCD, thereby promoting fatty acid utilization. The results show that high-fat feeding, fasting, and streptozotocin-induced diabetes all significantl...

The synthesis of long chain fatty acids from acetate in mammalian, extramitochondrial ("solu-ble") systems requires three enzymatic steps: 1) the activation of acetate to form acetyl-coenzyme A (acetyl-CoA), 2) the carboxylation of acetyl-CoA by the enzyme acetyl-CoA carboxylase to form malonyl-coenzyme A (malonyl-CoA), and 3) the subsequent complex series of serial condensations of malonyl-CoA...

The mitochondrial outer membrane enzyme carnitine palmitoyltransferase I (CPT I) plays a major role in the regulation of fatty acid entry into the mitochondrial matrix for beta-oxidation by virtue of its inhibition by malonyl-CoA. Two isoforms of CPT I, the liver type (L) and muscle type (M), have been identified, the latter being 100 times more sensitive to malonyl-CoA and having a much higher...

We have previously proposed that changes in malonyl-CoA sensitivity of rat L-CPT1 (liver carnitine palmitoyltransferase 1) might occur through modulation of interactions between its cytosolic N- and C-terminal domains. By using a cross-linking strategy based on the trypsin-resistant folded state of L-CPT1, we have now shown the existence of such N-C (N- and C-terminal domain) intramolecular int...

A yeast system differs only in that the major product is stearylCo.4 (5, 6) rather than the free fatty acid, palmitate, as in the other systems. The fatty acid synthetase reaction appears to be a multistage reaction catalyzed by a particulate enzyme complex estimated to have a molecular weight of 2,000,OOO in yeast (6) and to be readily sedimentable by ultracentrifugation in adipose tissue (4) ...