Regulation of Cell Growth and Tylosin Biosynthesis through Flux Control of Metabolic Intermediate in Streptomyces fradiae

Streptomyces fradiae에서 대사중간산물 이용속도에 의한 균체 성장과 tylosin 생합성의 조절

The aim of the present study was to investigate the effect of glutamate on the biosynthesis of tylosin. Activities of enzymes involved in the metabolic pathway of glutamate to form tylactone, an essential precursor of tylosin, were determined using Streptomyces fradiae grown at different concentration of glutamate. As results, it was found that cell growth and tylactone formation was controlled by the metabolic flux of oxaloacetate. It was clear that cell growth was favored by the activities of citrate synthase and aspartate aminotransferase, while the tylactone synthesis was stimulated by the activity of methylmalonyl-CoA carboxyltransferase. Therefore it was concluded that channelling of oxaloacetate was a point for favoring either cell growth or tylosin biosynthesis.

배지성분으로 첨가된 glutamate의 농도가 균의성장고 tylosin 생합성에 미치는 영향을 조사하였다. 그 결과 oxaloacetate를 공동기질로 사용하는 효소의 활성에 의하여 균의 성장과 tylosin의 생합성이 조절됨을 알았다. 즉, citrate synthase와 aspartate aminotransferase의 활성은 균의 성장에 아주 긴요하며 methylmalonyl-CoA carboxytransferase의 활성은 tylosin 생합성에 아주 중요한 효소임을 알았다. Glutamate의 농도는 우의 효소의 활성에 직접적으로 영향을 주고 있음을 알았다.