【摘要】 棕色固氮菌(Azotobacser Vinelandii—230)中与固氮酶共存的氢酶属于单向吸氢的氢酶,其中以粒子态存在者约占其总活力的78％,可溶态占22％。此二态酶对冷热稳定,最适反应温度和利用多种电子受体吸氢等方面均相似,但在耐热性、温度曲线的形式及对某些电子受体的亲和性方面有些差异。乙炔、Na~+离子及氧对酶的吸氢活力有抑制作用。菌体的氢酶活力,有氨培养比无氨培养的低86％左右;大量氨培养的UW—45菌体仍有氢酶活性,但比氨耗尽的UW45菌体低55％左右。钨代替钼培养的菌体无固氮酶活性,其粗提液氢酶活性也极低。由此可见,氢酶活性与固氮酶活性有极为密切的关系。更多还原

【Abstract】 From cell-free extract of Azotobacter vinelandii-230,two forms of H2 uptake hydrogenase were separated and characterized.Both the particiulate and the soluble forms exhibited stability against,cold and heat,giving simi lar optimal temperature,Acetylene,Na+ and oxygen inhibited the H2-uptake activity of the soluble form,while H2 recovered it effectively.The H2-uptake activity was 86% lower in bacterial cells from NH4+ containing me-dium than in that from NH4+-free medium.The H2-uptake activit of the UW-45 mutant cells harvested from NH4+ excess medium was 55% lower than that from NH4+-exhausted medium.On replacing Na2WO4 for Na2 MO4,neither nitrogenase activity nor hydrogenase activity could be dete cted.更多还原