浑球红假单胞菌及其谷氨酸合成酶突变株氢酶活性和合成  

Hydrogenase Activity and Synthesis in Whole Cells of Rhodobacter sphaeroides and Its GOGAT Mutant (Nif^-)

作　　者：杨大庆[1] 宋鸿遇[1] 

机构地区：[1]中国科学院上海植物生理研究所

出　　处：《植物生理学报（0257-4829)》1990年第3期220-226,共7页Acta Phytophysiologica Sinica

摘　　要：浑球红假单胞菌野生型菌株的氢酶表达被有机碳、氮底物所抑制。在光照和黑暗时,氧浓度变化对氢酶的作用不同,但高氧浓度都阻遏氢酶的表达。微量Ni^(2+)能专一性地促进氢酶活性,固氮酶的产氢也可以调节氢酶的表达水平。该野生菌株的GOGAT突变株缺乏固氮酶和氢酶活性,在加入谷氨酰胺合成酶抑制剂MSX后,固氮酶和氢酶以相关联的方式合成出来,固氮酶产生的氢看来诱导了氢酶的合成。然而在固氮酶不表达的情况下,外源氢也可诱导氢酶的合成。All organic carbon and nitrogen substrates tested repressed the expression of hydrogenase of Rhodobacter sphaeroides strain 601. Nickel added to the growing cells specifically stimulated the hydrogenase activity. The regulation of hydrogenase by O_2 in the light was different from that in the dark, but high content of O_2 (15% or 20%, v/v) repressed the hydrogenase synthesis under either condition. The high activity of hydrogenase was expressed under a growth condition allowing derepression of nitrogenase, but quite a low activity was observed in a medium containing NH_1^+ where there was no H_2 evolution. Nitrogenase and hydrogenase were induced by the treatment with MSX in the GOGAT deficient mutant of R. sphaeroides strain 601, which exhibited Nif^- and Hup^- phenotypes on a medium supplemented with glutamate, and the hydrogenase and nitrogenase synthesis proceeded in a coordinated manner. It appears that the hydrogen produced by the nitrogenase induced the synthesis of hydrogenase in growing cells. However, exogenous H_2 could also induce hydrogenase synthesis under growth conditions where synthesis of nitrogenase did not occur. From the above results, the possible relationship between hydrogenase and nitrogenase was discussed.

关 键 词：红假单胞菌 GOGAT突变株 氢酶 

分 类 号：Q945.13[生物学—植物学]