SOLUBLE GUANYLATE-CYCLASE FROM BOVINE LUNG - ACTIVATION WITH NITRIC-OXIDE AND CARBON-MONOXIDE AND SPECTRAL CHARACTERIZATION OF THE FERROUS AND FERRIC STATES
SOLUBLE GUANYLATE-CYCLASE FROM BOVINE LUNG - ACTIVATION WITH NITRIC-OXIDE AND CARBON-MONOXIDE AND SPECTRAL CHARACTERIZATION OF THE FERROUS AND FERRIC STATES
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DOI：
10.1021/bi00184a036
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发表时间：
1994-05-10
期刊：
影响因子：
2.9
通讯作者：
MARLETTA, MA
中科院分区：
文献类型：
--
作者：
STONE, JR;MARLETTA, MA
一氧化氮((NO)-N-。)是一种新近发现的信号转导因子，在血管扩张和神经元突触传递等许多生物学过程中发挥作用。到目前为止以(NO)-N-为特征的唯一受体。是鸟苷环化酶(SGC)的可溶性形式。(否)-N-。可能通过与酶上的血红素部分相互作用，使sGC的V-max增加100-200倍。虽然存在几种提纯sGC的方法，但这些方法所得到的制剂中的血红素含量较低。用一种新的方法，从牛肺中提纯了该酶，其血红素含量约为1个血红素/异二聚体。该酶的紫外-可见光谱包含一个位于431 nm的Soret峰和一个位于555 nm的宽的α/β峰，表明该酶是以组氨酸为轴向配体的5配位亚铁血红素。血红素部分不结合氧，但容易结合(NO)-N-。形成5配位络合物或一氧化碳(CO)形成6配位络合物。用铁氰化物氧化血红素使Soret移动到393 nm，这最有可能是由于形成了一个5配位的铁血红素。在铁的状态下，与高铁血红蛋白和高铁肌红蛋白相比，血红素显然不会与水结合，但会与氰化物结合，亲和力降低。含有1个血红素/杂二聚体的纯化酶可被(NO)-N-激活130倍。是CO的4.4倍。
Nitric oxide ((NO)-N-.) is a recently discovered signaling agent which plays a role in many biological processes such as vasodilation and neuronal synaptic transmission. The only receptor characterized thus far for (NO)-N-. is the soluble form of guanylate cyclase (sGC). (NO)-N-. increases the V-max of sGC by 100-200-fold, probably by interacting with a heme moiety on the enzyme. Although several procedures exist for purifying sGC, these procedures result in preparations with low heme contents. Using a novel procedure, the enzyme has been purified to homogeneity from bovine lung with a heme content of approximately 1 heme/heterodimer. The UV-visible spectrum of the enzyme contains a Soret peak centered at 431 nm and a single broad alpha/beta peak at 555 nm indicative of a 5-coordinate ferrous heme with histidine as the axial ligand. The heme moiety does not bind oxygen but will readily bind (NO)-N-. to form a 5-coordinate complex or carbon monoxide (CO) to form a 6-coordinate complex. Oxidation of the heme with ferricyanide shifts the Soret to 393 nm, due most likely to the formation of a 5-coordinate ferric heme. In the ferric state, the heme will apparently not bind water but will bind cyanide with reduced affinity compared to methemoglobin and metmyoglobin. Purified enzyme containing 1 heme/heterodimer is activated 130-fold by (NO)-N-. and 4.4-fold by CO.