- 著者
-
高橋 宣治
内田 健一
中川 彰
松崎 桂一
大村 智
中村 朝朗
三宅 洋子
武 佳和
甲斐荘 正恒
- 出版者
- 天然有機化合物討論会実行委員会
- 雑誌
- 天然有機化合物討論会講演要旨集
- 巻号頁・発行日
- vol.35, pp.762-768, 1993
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.