Enzymatic dehydrogenation of cyclo(L-Phe-L-Leu) to a bioactive derivative,albonoursin

The cell-free extract of Streptomyces sp. KO-2388, an albonoursin-producing strain, was found to catalyze the conversion of cyclo(L-Phe-L-Leu) to albo noursin. The conversion activity was simply determined by measuring the inc rease in ultraviolet (UV) absorption of the reaction mixture at 317 nm, lam bda(max) (epsilon 25,400) of albonoursin, where cyclo(L-Phe-L-Leu) had no a bsorption. The optimum pH and temperature of this bioconversion using the c ell-free extract were determined to be pH 8.0-9.5 and 60 degrees C, respect ively. Under the optimum conditions, 620 mg/l of albonoursin was obtained w ith a conversion ratio of 62% after 24 h incubation. (C) 1999 Elsevier Scie nce B.V. All rights reserved.