Hyman M R, Wood P M
Biochem J. 1985 May 1;227(3):719-25. doi: 10.1042/bj2270719.
Acetylene brings about a progressive inactivation of ammonia mono-oxygenase, the ammonia-oxidizing enzyme in Nitrosomonas europaea. High NH4+ ion concentrations were protective. The inactivation followed first-order kinetics, with a rate constant of 1.5 min-1 at saturating concentrations of acetylene. If acetylene was added in the absence of O2, the cells remained active until O2 was re-introduced. A protective effect was also demonstrated with thiourea, a reversible non-competitive inhibitor of ammonia oxidation. Incubation of cells with [14C]acetylene was found to cause labelling of a single membrane polypeptide. This ran on dodecyl sulphate/polyacrylamide-gel electrophoresis with an Mr value of 28 000. It is concluded that acetylene is a suicide substrate for the mono-oxygenase. The labelling experiment provides the first identification of a constituent polypeptide of ammonia mono-oxygenase.
乙炔会导致欧洲亚硝化单胞菌中氨氧化酶——氨单加氧酶的逐步失活。高浓度的NH4+离子具有保护作用。失活遵循一级动力学，在乙炔饱和浓度下速率常数为1.5分钟-1。如果在无氧条件下添加乙炔，细胞在重新引入氧气之前仍保持活性。硫脲（一种氨氧化的可逆非竞争性抑制剂）也表现出保护作用。发现用[14C]乙炔孵育细胞会导致一种单一膜多肽被标记。该多肽在十二烷基硫酸钠/聚丙烯酰胺凝胶电泳上的Mr值为28000。得出的结论是，乙炔是单加氧酶的自杀底物。标记实验首次鉴定出氨单加氧酶的一种组成多肽。
