Stone J R, Sands R H, Dunham W R, Marletta M A
Department of Biological Chemistry, School of Medicine, University of Michigan, Ann Arbor 48109-1065.
Biochem Biophys Res Commun. 1995 Feb 15;207(2):572-7. doi: 10.1006/bbrc.1995.1226.
Nitric oxide (.NO) is an important intercellular signaling agent throughout the animal kingdom. The majority of the effects of .NO is due to the direct stimulation of soluble guanylate cyclase (sGC). It has been proposed that .NO activates sGC by interacting with a heme moiety on the enzyme. The electron paramagnetic resonance (EPR) spectra of the ferrous-[14N/15N]nitrosyl complexes of the purified enzyme have been obtained. The spectrum of the [14N]nitrosyl-sGC complex was almost identical to that of a 5-coordinate. Hyperfine coupling constants and g-values were determined from computer simulations of the EPR spectra. Electronic absorption spectroscopy was used to show that the 5-coordinate nitrosyl complex on sGC forms under conditions that are typically used to assay activation of the enzyme.
一氧化氮（·NO）是整个动物界重要的细胞间信号传导介质。·NO的大部分作用是由于对可溶性鸟苷酸环化酶（sGC）的直接刺激。有人提出，·NO通过与酶上的血红素部分相互作用来激活sGC。已获得纯化酶的亚铁-[14N/15N]亚硝酰配合物的电子顺磁共振（EPR）光谱。[14N]亚硝酰-sGC配合物的光谱与五配位配合物的光谱几乎相同。通过EPR光谱的计算机模拟确定了超精细偶合常数和g值。电子吸收光谱用于表明，sGC上的五配位亚硝酰配合物是在通常用于测定该酶激活的条件下形成的。
