Interaction of Long‐Chain Acyl‐CoA Analogs with Pig Kidney General Acyl‐CoA Dehydrogenase

Abstract
The interaction of 2 long-chain acyl-CoA analogs with pig kidney general acyl-CoA dehydrogenase (EC 1.3.99.3) was examnined. The effect of S-heptadecyl-CoA and heptadecan-2-onyl-dethio-CoA on the flavoprotein was observed spectrophotometrically using the flavin as an active-site probe. The S-heptadecyl thioether analog bound strongly to the enzyme (Kd = 17 nM) and was a powerful competitive inhibitor (Kj < 40 nM). In contrast to the thioether analog, the dethiocarba derivative, heptadecan-2-onyl-dethio-CoA, was a substrate in the standard assay system being dehydrogenated at .apprx. 60% of the rate shown by palmitoyl-CoA. Apparently .alpha.-carbanion formation is an early event in the dehydrogenation of acyl-CoA substrates.