The antibiotic polyoxin D was shown to inhibit the incorporation of (14)C-glucosamine into cell wall chitin in Neurospora crassa at levels which were comparable with those required for inhibition of fungal growth. At the same time, the antibiotic increased the accumulation of a nucleotide, which was identified as uridine diphosphate (UDP)-N-acetylglucosamine, indicating inhibition of chitin synthesis. Chitin synthetase (UDP-N-acetylglucosamine: chitin N-acetylglucosaminyl transferase, EC 2.4.1.16) of N. crassa was found to be strongly inhibited by polyoxin D, as determined by the transfer of (14)C-N-acetylglucosamine from (14)C-UDP-N-acetylglucosamine to the particulate fraction. The inhibition was competitive with respect to UDP-N-acetylglucosamine and specific for chitin synthetase. The K(i) for polyoxin D in the reaction was 1.40 x 10(-6)m, and the K(m) for UDP-N-acetylglucosamine was 1.43 x 10(-3)m. The formation of osmotically sensitive, protoplast-like structures, when the fungus Cochliobolus miyabeanus was grown in the presence of polyoxin D, also suggested that the primary site of action of polyoxin D was in the formation of cell wall structures.

中文翻译：

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抗真菌剂多毒素D的作用机理。

已显示抗生素多聚毒素D以与抑制真菌生长所需的水平相当的水平抑制（14）C-葡萄糖胺掺入到克氏梭菌中的细胞壁甲壳质中。同时，抗生素增加了核苷酸的积累，该核苷酸被鉴定为二磷酸尿苷（UDP）-N-乙酰氨基葡萄糖，表明甲壳质合成受到抑制。如通过（14）从（14）中的（14）CN-乙酰氨基葡萄糖的转移所确定的那样，发现多孢菌素D强烈抑制了猪笼草的几丁质合成酶（UDP-N-乙酰氨基葡萄糖：几丁质N-乙酰氨基葡萄糖转移酶，EC 2.4.1.16）。 C-UDP-N-乙酰氨基葡萄糖的颗粒部分。该抑制对于UDP-N-乙酰基葡糖胺而言是竞争性的，并且对于几丁质合成酶是特异性的。反应中多聚毒素D的K（i）为1.40 x 10（-6）m，UDP-N-乙酰氨基葡萄糖的K（m）为1.43 x 10（-3）m。当真菌Cochliobolus miyabeanus在多毒素D的存在下生长时，渗透敏感的原生质体样结构的形成也表明，多毒素D的主要作用部位是细胞壁结构的形成。