Purification of a 15-ketoprostaglandin delta 13-reductase from rat liver and its ability to reduce the double bond of xenobiotics.

A 15-ketoprostaglandin delta 13-reductase was purified to homogeneity from rat liver. The enzyme used NADPH much more effectively than NADH as an electron donor. The molecular weight was estimated to be 39,500 by electrophoresis and 42,000 by gel filtration. The Km apparent for 15-ketoprostaglandin F2 alpha was 213 nM. The enzyme was markedly inhibited by dicumarol, quercitrin, p-chloromercuribenzoic acid and indomethacin. The enzyme had an isoelectric point at pH 4.5 and a broad pH optimum. The enzyme also exhibited the double bond reductase activity toward several xenobiotics with the double bond adjacent to the carbonyl group.