Biosynthesis of acaterin: Mechanism of the reaction catalyzed by dehydroacaterin reductase

Dehydroacaterin reductase is an enzyme which catalyzes the final step of acaterin biosynthesis, that is, the reduction of the C-4/C-5 double bond of dehydroacaterin. The mechanism of the reduction was investigated with a cell-free preparation obtained from the acaterin-producing microorganism, Pseudomonas sp. A 92. Incubation of dehydroacaterin in the presence of [4,4-H-2(2)]NADPH or D2O followed by H-2 NMR analysis of the resulting acaterin revealed that the deuterium atom from NADPH was incorporated into the C-5 position of acaterin, while the deuterium atom from D2O was introduced into the C-4 position. It was further demonstrated that the pro-R hydrogen at C-4 of NADPH was stereo specifically utilized in this reduction. (c) 2006 Elsevier Ltd. All rights reserved.