STUDIES ON NEW DOUBLE BOND REDUCTASES

Abstract

Purification and characterization of the double bond reductases in mammalian species, bacteria and fish was performed. The NADPH- and NADH-linked double bond reductase activities towards 15-ketoprostaglandin F_1α, F_2α E₂, and E₂ were observed in rat liver cytosol. Five kinds of 15-ketoprostaglandin Δ¹³-reductases were isolated and purified from rat liver by chromatography on columns of DEAE-cellulose, hydroxyapatite, Blue-toyopearl and phenyl-toyopearl. These enzyme activities were not influence by oxygen, but inhibited by dicumarol and quercitrin. Some of these enzyme exhibited the double bond reductase activities towards benzylideneacetone and phenyl propenyl ketone. However, the double bonds of prostaglandin E₁, stilbene and testosterone were not reduced by these enzymes. Salmonella typhimurium exhibited a significant double bond reductase activity toward phenyl propenyl ketone. NAD(P)H-linked and NADPH-linked double bond reductase were isolated from cell-free extract of Salmonella typhimurium. NAD(P)H-linked enzyme was purified from the cell-free extract by chromatography on columns of DEAE-cellulose, hydroxyapatite and Phenyl-toyopearl. The enzyme activity was also oxygen-insensitive, but susceptible to inhibited by dicumarol. 15-Ketoprostaglandins were also reduced with the enzyme. Three double bond reductase activities toward phenyl propenyl ketone were isolated from sea-bream liver cytosol by DEAE-cellulose column chromatography. Thus, a variety of double bond reductases were found in mammalian species, fish and bacteria.