Microbial transformation of immunosuppressive compounds III. Glucosylation of immunomycin (FR 900520) and FK 506 byBacillus subtilis ATCC 55060

Abstract

The regiospecific glucosylation of FK 506 and immunomycin (FR 900520) at the 24-hydroxy position was performed using resting cells of Bacillus subtilis ATCC 55060. 24-Glucopyranosyl FK 506 and 24-glucopyranosyl immunomycin were isolated by methylene chloride extraction and purification using reverse phase HPLC. The metabolite structures were established using spectroscopic techniques including MS and NMR. The glucose conjugate was further confirmed by chemical degradation. Enzymatic glucosylation was demonstrated using cell-free extracts derived from Bacillus subtilis ATCC 55060. The 24-glucosyltransferase, which appears UDP-glucose dependent, was solubilized from cell membranes by treatment with 0.1% Nonidet P-40 detergent. The optimal conditions for assay of the enzyme have been determined.

Glycosylation employing bio-systems: from enzymes to whole cells

“…There exist few examples, in which living microbial cells were used for glycosylations. An example of the glycosylation of a rather complicated molecule by resting cells of Bacillus subtilis is a preparation of the 24-O-b-glucopyranoside of the immunosuppressive drugs FK 506 and of immunomycin 29 (Scheme 19). A strict regioselectivity of the enzyme can be noted because glycosylation at only one of the three available OH groups occurs.…”