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将~(13)C-高含量的前体——乙酸与丙酸加入Nocardia mediterranei的发酵液中,得到~(13)C-高含量的利福霉素B,转化为利福霉素S后,用~(13)C-核磁共振谱确定各个碳原子的生源。由不同标记的前体进行试验。结果证实,在利福霉素结构中含有萘环发色团的安沙环(Ansa chain)是由五个丙酸单元和两个乙酸单元按顺钟向依次缩合而成。在利福霉素的生物合成过程中,C-12、C-13、C-29丙酸单元裂解,并在C-12与C-29之间插入一氧原子,而在C-28上的丙酸单元甲基掉失。芳香发色团部分只有一个乙酸单元参入,芳香化合物的另一前体莽草酸不参入,
The ~ (13) C-high content precursor-acetic acid and propionic acid were added into the fermentation broth of Nocardia mediterranei to obtain ~ (13) C- high content of rifamycin B, which was transformed into rifamycin S The source of each carbon atom was determined by ~ (13) C-nuclear magnetic resonance spectroscopy. Experiments were conducted with different labeled precursors. As a result, it was confirmed that Ansa chain containing a naphthalene ring chromophore in the structure of rifamycin is formed by sequential condensation of five propionic acid units and two acetic acid units in sequence. In the biosynthesis of rifamycin, the C-12, C-13, C-29 propionic acid units are cleaved and an oxygen atom is inserted between C-12 and C-29, while at C-28 Propionic acid unit methyl lost. Aromatic chromophore part of only one acetic acid unit participation, the other precursor of aromatics shikimic acid does not participate,