微生物由来のジケトピペラジン環化合物代謝酵素による生理活性物質生産

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iketopiperazines(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-producing 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 α, β-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 clevage of sea urchin embrvo 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.
社団法人日本生物工学会の論文
2001-03-25