Purification of an alpha,beta-ketoalkene double bond reductase from Salmonella typhimurium

An alpha, beta-ketoalkene double bond reductase was purified from the cell-free extract of Salmonella typhimurium. The purified enzyme was homogeneous by the criterion of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight of the enzyme was estimated to be 24,700 by the electrophoresis and 23,900 by HPLC gel filtration, respectively. The isoelectric point is pH 7.2. The enzyme in the presence of NAD(P)H exhibited double bond reductase activity toward alpha, beta-ketoalkenes such as trans-phenyl-1-propenyl ketone, trans-benzylideneacetophenone and 15-ketoprostaglandins. The enzyme activity was markedly inhibited by dicumarol.