Production of Bioactive Compounds by Microbial Diketopiperazine-Metabolizing Enzymes. Monograph.

Accession number;01A0447391
Title;Production of Bioactive Compounds by Microbial Diketopiperazine-Metabolizing Enzymes. Monograph.
Author; KANZAKI HIROSHI (Okayama Univ., Graduate School of Natural Sci. and Technol., JPN)
Journal Title;Seibutsu Kogakkaishi
Journal Code:G0440B
ISSN:0919-3758
VOL.79;NO.3;PAGE.71-77(2001)
Figure&Table&Reference;FIG.4, REF.45
Pub. Country;Japan
Language;Japanese
Abstract;Diketopiperazines(DKPs) and their derivatives are widely distributed in nature as secondary metabolites. Although some dehydroDKPs are known as cell cycle inhibitors, their effective synthesis has not been reported. We found that the cell-free extract from an albonoursin-producting actinomycete, Streptomyces albulus KO23, catalyzed the conversion of cyclo (Leu-Phe) to albonoursin. This is the first report on the dehydrogenation of amino acid residues at the .ALPHA., .BETA.-positions in DKPs. Furthermore, this enzyme system enabled us to synthesize several didehydro- and tetradehydro-DKPs from the corresponding DKPs. Among the dehydroDKPs prepared, dehydrophenylahistin from (-)-phenylahistin, which was recently reported to be a new cell cycle inhibitor, exhibited 1000 times higher inhibitory activity toward the first cleavage of sea urchin embryo than (-)-phenylahistin, and would thus be a promising lead compound for antitumor agents. Agrobacterium radiobacter NM 5-3 isolated from soil hydrolyzed CGL to from dipeptides (i.e., Leu-Gly and Gly-Leu) and amino acids (i.e., Leu and Gly). This CGL hydrolysis was catalyzed by two distinct enzymes, CGLase and dipeptidase, which were separated by anion-exchange column chromatography. The CGLase was found to catalyze the hydrolysis of CGDL, CGG, CAG, and CDAG. On the other hand, the dipeptidase exhibited L-specific substrate specificity. (author abst.)