98 放線菌の生産する神経突起伸長作用物質ラクタシスチンの生合成研究(ポスター発表の部)

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The biosynthesis of lactacystin, a new microbial metabolite which induces differentiation of neuroblastoma cells, was studied by ^<13>C NMR spectroscopy using various ^<13>C labeled precursors. The feeding experiment of L-[2-^<13>C ] leucine showed a strong enrichement at C-5 of Lactacystin. Incorporation of [1-^<13>C] isobutyrate labeled C-1, C-4, C-8, and C-14. These ^<13>C labeling patterns indicate that lactacystin consists of three biosynthetic units, namely isobutyrate (or L-valine), L-leucine, and L-cysteine. The C_<10> unit containing γ-lactam moiety arises by a condensation between methylmalonate semialdehyde and C-5 of the C_6 unit derived biosynthetically from L-leucine, followed by intramolecular cyclization. The stereochemistry of two diastereotopic methyl carbons of lactacystin which appeard at δc 19.85 and δc 21.37 was investigated by incorporation of a new type of chiral ^<13>C L-leucine (or L-valine), designated as the ^<13>C block labeled leucine (or valine), which was obtained from the fermentation of leucine producing organism using a mixture of 99% [U-^<13>C_6] glucose and natural glucose as a carbon source.
天然有機化合物討論会の論文
1993-09-10