Modification of a specific tyrosine residue of ribonuclease A with a diazonium inhibitor analog.

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… CONTINUE READING