Medium-chain acyl coenzyme A dehydrogenase from pig kidney has intrinsic enoyl coenzyme A hydratase activity

Sze Mei Lau, Pat Powell, Hermann Buettner, Sandro Ghisla, Colin Thorpe
1986 Biochemistry  
The flavoprotein medium-chain acyl coenzyme A (acyl-CoA) dehydrogenase from pig kidney exhibits an intrinsic hydratase activity toward crotonyl-CoA yielding L-3-hydroxybutyryl-CoA. The maximal turnover number of about 0.5 min-' is 500-1000-fold slower than the dehydrogenation of butyryl-CoA using electron-transferring flavoprotein as terminal acceptor. trans-2-Octenoyl-and trans-2-hexadecenoyl-CoA are not hydrated significantly. Hydration is not due to contamination with the short-chain
more » ... short-chain enoyl-CoA hydratase crotonase. Several lines of evidence suggest that hydration and dehydrogenation reactions probably utilize the same active site. These two activities are coordinately inhibited by 2-octynoyl-CoA and (me-thylenecyclopropy1)acetyLCoA [whose targets are the protein and flavin adenine dinucleotide (FAD) moieties of the dehydrogenase, respectively]. The hydration of crotonyl-CoA is severely inhibited by octanoyl-CoA, a good substrate of the dehydrogenase. The apoenzyme is inactive as a hydratase but recovers activity on the addition of FAD. Compared with the hydratase activity of the native enzyme, the 8-fluoro-FAD enzyme exhibits a roughly 2-fold increased activity, whereas the 5-deaza-FAD dehydrogenase is only 20% as active.
doi:10.1021/bi00363a003 pmid:3756134 fatcat:gay6ddoxiff2hgcvzrsruqwcda