Study On The Biosynthesis Of Apramycin

The biosynthesis pathway of apramycin in S.tenebrariuswas studied in this paper by using S.tenebrarius 1-16,the apramycin-producing strain, and its mutants of low-product strains such as strain No.90 as well as mutants fully blocked in the biosynthesis of apramycin such as Dl0l.The ?C-NMR results of isotopes-incorporating experiment showed that [2- 13C,15N]-serine participated in the biosynthesis of apramycin. The labelled nitrogen atoms were found in five positions of apramycin while the labelled carbon atoms were not found in apramycin molecular. The results confirmed that serine is the nitrogen donor to apramycin biosynthesis. The quantitative analysis results of S-adenosylmethionine(SAM) in mycelium indicated that the possible pathway of the methyl-group on nitrogen atom at C? position of apramycin. was provided by glycine. The proposed route is that the carbon of the methyl- group came from glvcine, through N5-CH3-FH4, methionine to SAM,and then was transferred to nitrogen atom at C? position of apramycin.The results of feeding wild strain S.tenebrarius 1-16, low-product mutants and biosynthesis blocked mutants with precursors showed that 2-DOS (2-deoxystreptamine)paromamine,aprosamine are the precursors of apramycin biosynthesis. According to the above results and the results of cosynthesis , the proposed pathway of apramycin biosynthesis was brought forward.Theorine and its structural analog a -amino- P -hydroxylvaleric acid (AHV) increased apramycin production greatly.11A procedure was set up to prepare 2-DOS , octodiosamine and aprosamine by hydrolyzing apramycin , and to prepare paromamine from apramycin.