Chen Y, Rosazza J P
Division of Medicinal and Natural Products Chemistry, College of Pharmacy, University of Iowa, Iowa City 52242.
Biochem Biophys Res Commun. 1994 Sep 15;203(2):1251-8. doi: 10.1006/bbrc.1994.2317.
Nitric oxide synthase (EC 1.14.23) was discovered in a Nocardia species. The bacterial nitric oxide synthase was purified as much as 380 fold by affinity chromatography over 2',5'-ADP-agarose. The partially purified enzyme required NADPH, O2, CA++, FAD, FMN, and tetrahydrobiopterin as cofactors in the conversion of L-arginine to L-citrulline and nitric oxide. The apparent Km for L-arginine was determined to be 8.2 microM, and the Vmax was 840 nmole NADPH consumed/min/mg protein. The enzyme was competetively inhibited by NG-nitro-arginine with an apparent Ki of 14.6 microM. The experimental evidence provides confirmation of the first microbial nitric oxide synthase in microorganisms.
一氧化氮合酶（EC 1.14.23）是在一种诺卡氏菌属细菌中发现的。通过在2',5'-ADP-琼脂糖上进行亲和层析，细菌一氧化氮合酶被纯化了多达380倍。部分纯化的酶在将L-精氨酸转化为L-瓜氨酸和一氧化氮的过程中，需要NADPH、O₂、Ca²⁺、FAD、FMN和四氢生物蝶呤作为辅助因子。L-精氨酸的表观Km值测定为8.2微摩尔，Vmax为每分钟每毫克蛋白质消耗840纳摩尔NADPH。该酶被NG-硝基精氨酸竞争性抑制，表观Ki为14.6微摩尔。实验证据证实了微生物中首个微生物一氧化氮合酶的存在。
