Gupta M N, Vithayathil P J
Int J Pept Protein Res. 1980 Mar;15(3):236-42. doi: 10.1111/j.1399-3011.1980.tb02572.x.
The accessibility of methionines in RNAase A to reaction with OBQ has been studied at highly acidic pH. The differences between the rate constants of reactions of the methionine and methionines of RNAase A with OBQ is a reflection on the limited accessibility of methionines in the protein conformation. Nevertheless, at sufficiently high OBQ concentration, all the four methionines of the enzyme can be modified. At lower concentration of OBQ, a derivative may be prepared in which a specific methionine is modified. The introduced chromophore ionizes at around pH 3 in this derivative. The derivative has partial activity towards RNA which is enhanced on addition of S-protein.
在高酸性pH条件下，对核糖核酸酶A中蛋氨酸与OBQ反应的可及性进行了研究。核糖核酸酶A中蛋氨酸与OBQ反应的速率常数差异反映了蛋白质构象中蛋氨酸的可及性有限。然而，在足够高的OBQ浓度下，该酶的所有四个蛋氨酸都可以被修饰。在较低的OBQ浓度下，可以制备一种特定蛋氨酸被修饰的衍生物。在这种衍生物中，引入的发色团在pH约为3时发生电离。该衍生物对RNA具有部分活性，在添加S蛋白后活性增强。
