Gorecki M, Wilchek M
Biochim Biophys Acta. 1978 Jan 25;532(1):81-91. doi: 10.1016/0005-2795(78)90450-6.
The diazonium salt of 5'-(4-aminophenyl phosphoryl)-uridine 2'(3')-phosphate reacts stoichiometrically with pancreatic ribonuclease and modifies only one tyrosyl residue, which was identified as Tyr 73 in the amino acid sequence. The modification does not inhibit the biological activity of RNAase on ribonucleic acid, although a large change in the binding constant towards cytidine cyclic phosphate was observed. The modification can be inhibited by addition of the competitive inhibitor cytidine 2'(3')5'-diphosphate and may indicate that Tyr 73 is the most exposed residue or has a unique reactivity towards this reactive substrate analog.
5'-(4-氨基苯基磷酰基)-尿苷2'(3')-磷酸的重氮盐与胰腺核糖核酸酶按化学计量反应，仅修饰一个酪氨酸残基，该残基在氨基酸序列中被鉴定为Tyr 73。尽管观察到对环胞苷磷酸的结合常数有很大变化，但这种修饰并不抑制核糖核酸酶对核糖核酸的生物活性。加入竞争性抑制剂2'(3')5'-二磷酸胞苷可抑制这种修饰，这可能表明Tyr 73是最暴露的残基，或者对这种反应性底物类似物具有独特的反应性。
