Open AccessMultiple Carboxymethylation of Histidines in Bovine Ribonuclease A
Author(s) -
Bello Jake,
Nowoswiat Eugène F.
Publication year - 1971
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1971.tb01536.x
Subject(s) - histidine , chemistry , methionine , alkylation , histidine decarboxylase , stereochemistry , derivative (finance) , bovine pancreatic ribonuclease , active site , lysine , ribonuclease t1 , ribonuclease , biochemistry , enzyme , amino acid , rna , gene , financial economics , rnase p , economics , catalysis
Reaction of RNAase A with bromoacetate at pH 5.5 for 1–42 days results in multiple reactions. Alkylation of residues proceeds in the sequence: (1) N‐1 of histidine‐119; (2) methionine (probably methionine‐30); (3) N‐3 of histidine‐12; (4) N‐3 of histidine‐105 and N‐3 of 1‐carboxy‐methyl histidine‐119; and (5) lysine‐1. Both histidine‐12 and histidine‐119 of the same active site are carboxymethylated. A derivative carboxymethylated at both active site histidines is obtained in 1 day and probably some of this derivative is obtained in short reaction times. This is contrary to the conclusions of earlier investigations. Histidine‐48 undergoes little or no reaction. The results are in accord with the X‐ray structure of RNAase.