地中海拟无枝菌酸菌U-32对硝酸盐的同化及其硝酸还原酶特性北大核心

对地中海拟无枝菌酸菌U-32菌株的研究发现,像植物及真菌硝酸还原酶一样,地中海拟无枝菌酸菌U-32硝酸还原酶也是诱导酶,其合成受铵盐阻遏,受硝酸盐的诱导。氯霉素抑制实验的结果表明,该菌株硝酸还原酶的诱导涉及到蛋白质的新合成。钼和钨的竞争实验说明U-32菌株硝酸还原酶也为一钼酶。另外在离体实验中,发现硝酸还原酶活力受到KCN和NADH的抑制,但至今未能找到其生理电子供体。此外,U-32菌株硝酸还原酶也不表现类似于植物的黄递酶等组份酶活性。该菌株硝酸还原酶和其力复霉素产量有一定相关性,但两者确切的关系尚待研究。

NITRATE ASSIMILATION OF AMYCOLATOPSIS MEDITERRANEl U-32 AND SOME PROPERTIES OF ITS NITRATE REDUCTASE

Preliminary results indicate that NR of Amycolatopsis mediterranei U-32, like that of plants and fungi, is also an inducible enzyme. Its synthesis is induced by nitrate and repressed by ammonia and other readily usable nitrogen sources. Chloramphenicol inhibitory experiment shows that NR induction involves de novo synthesis of proteins. Competition between molybdate and tungstate in NR synthesis suggested that NR of A. mediterranei U-32 is a molybdenumcontaining enzyme. NR activity in crude extract is inhibited by KCN and NADH. The natural electron donor of NR is still unknown. Beside, NR of A. mediterranei U-32 does correlation between rifamycin SV productivity to specific activity of mycelial nitrate reductase.