41 シッカニンの生合成

抄録

Trans-γ-monocyclofarnesol (VI) was found to be formed by the incubation of mevalonio acid lactone with the soluble enzyme preparations from the mycelia of Helminthosporium siccans, which was known to produce an antibiotic, siccanin (I). 4,8,14-^<14>C-farnesyl pyrophospahte (XI) was also shown to convert to VI by the same incubation condition. In the presence of the joint substrate, orsellinic acid, the product of the enzymic reaction was found to be siccanochromene-A (III). Divaricatinic acid, oroinol, resorcinol, and resorcylic acid did not act as a substrate of this enzymic reaction. Tritium labelled siccanochromenic acid (III), siccanochromea-A (IV), and siccanochromene-B (V) were effectively incorporated into siccanin (I) by the incubation with the intact growing cell systems of H. siccans.