Enzymatic oxidation of steroids by cell-free extracts of Pseudomonas testosteroni: isolation of cleavage products of ring A.

Abstract

Ultracentrifuged enzyme extracts from steroid-induced lyophilized cells of P. testosteroni supplemented with diphosphopyridine nucleotide (DPN) and a reduced triphosphopyridine nucleotide (TPNH) generating system oxidatively degrade the C skeleton of [DELTA]4-androstene-3,17-dione-4-C14, releasing almost all of the label as c14O2. In the presence of ethylenediamine tetraacetate, these systems accumulate DL-alanine-1-C14 and L-2-amino-cis-4-hexenoic acid-1-C14 (both of which carry the label in their carboxyl groups). The identification of the amino-acids is based on their chromatographic behavior, infrared and nuclear magnetic resonance spectra, and the catalytic hydrogenation of the L-2-amino-cis-4-hexenoic acid to L-norleucine. A sequence of enzymatic reactions is proposed, whereby these amino-acids can be derived from ring-A of the steroid.