【摘要】 野生型金色链霉菌A-94同时产生制霉菌素和放线酮。人为处理获得单向生物合成制霉菌素不产生放线酮及两者均不产生的缺失株。利用上述阻断变株进行制霉菌素生物合成调控的研究,发现单缺失株A₃制霉菌素的高产是由于阻断戊二酰亚胺合成支路,而与羧化酶的活性不成正比。发现金色链霉菌A-94存在对称生物合成系统,制霉菌素的旋光异构体D及L型已分离得到,两者均具有相近的生物活性。此外,对金色链霉菌A-94生物合成的可能途径进行了探讨。更多还原

【Abstract】 The paper deals with a study on antibi-otic biosynthesis of nystatin by use of blocked mutants which were deleted in structural genes responsible for glutarimide and both glutarimide and nystatin biosynthesis. Nystatin was overproduced by glutarimide negative mutant.The biosynthesis of nystatin isindependent to the glutarimide shunt and not proportional to the common carboxylase activities.Symmetrical biosynthesis system for optically active isomer of nystatin was found to present in Streptomyces aureus A-94, both D and L-form nystatin have been successfully isolated.Surprisingly that the Levo-nystatin possesses about the same biological activity as the Dextro-form.A proposed scheme for the biosynthesis pathways of Streptomyces aureus A-94 is discussed.更多还原