Studies on the 3-Ketosteriod-1-Dehydrogenation of Steroid Hormone by Cellular lysates of Mycobacterium
10.13523/j.cb.20170804
- VernacularTitle:分枝杆菌细胞裂解液催化甾体激素C1,2位脱氢反应的研究
- Author:
Mengfei QIN
;
Hong SUN
;
Hao SONG
- Keywords:
9β,11β-Epoxypregn-1,4-diene-17α,21-diol-3,20-dionecellular;
Lysates of Mycobacterium;
3-ketosteriod-1-dehydrogenase
- From:
China Biotechnology
2017;37(8):23-30
- CountryChina
- Language:Chinese
-
Abstract:
9β,11β-Epoxypregn-4-ene-17α,21-diol-3,20-dione 21-acetate (Ⅰ) is a substrate for the production of 9β,11β-Epoxypregn-1,4-diene-17α,21-diol-3,20-dione (Ⅳ),which is a key precursor for the production of many 9-fluoro-substituted corticosteroid hormones.By comparing whole cells catalysis and cellular lysates conversion,it was found that whole cells of Mycobacterium sp.MS136 could only convert Ⅰ to 9β,11β-Epoxypregn-4-ene-17α,21-diol-3,20-dione (Ⅱ),and Ⅰ can be effectively converted toⅣ by cellular lysates.The reaction order is that Ⅰ is spontaneously hydrolyzed to Ⅱ and Ⅱ undergoes C1,2-dehydrogenation reaction to Ⅳ.In order to improve the productivity of Ⅳ,the key genes kstD,kstD3 and kstDM encoding C1,2-dehydrogenase (KSTD) were overexpressed in Mycobacterium sp.MS136 to enhance the C1,2-dehydrogenation reaction rate,and the results showed that 1 g/L substrate Ⅰ can be converted by recombinant strain MS136-kstDM cellular lysates at pH 7.0,the productivity of Ⅳ reached 78.4％ after 45 h,which is 38.9％ higher than original strain.The reaction rate is enhanced by optimizing the pH,and the results showed that 1 g/L substrate (Ⅰ) can be converted by recombinant strain MS136-kstDM cellular lysates at pH 7.5,the productivity of Ⅳreached 92.8％ after 45 h,which was 63.4％ higher than original strain.
