1. Adenosine deaminase was inactivated by 9-(4-bromoacetamidobenzyl)-adenine (I) and 9-(2-bromoacetamidobenzyl)adenine (II), two affinity labels. 2. The stoichiometry of the reaction with reagent II is reported: 1 mol reagent is bound per mol inactive enzyme. Amino acid analysis of the 6 N HCl hydrolyzate of the inactive enzyme identified CM-histidine as the main alkylation product. This is the first evidence of the presence of a histidine in the active site region. 3. The alkylation rate and involved amino acid residues were studied for both reagents I and II, at pH 8 and 5.5. The particular reactivity of a lysine near or in the active site is discussed.
AFFINITY LABELING OF HISTIDINE AND LYSINE RESIDUES IN THE ADENOSINE-DEAMINASE SUBSTRATE BINDING-SITE
LUCACCHINI, ANTONIO;
1979-01-01
Abstract
1. Adenosine deaminase was inactivated by 9-(4-bromoacetamidobenzyl)-adenine (I) and 9-(2-bromoacetamidobenzyl)adenine (II), two affinity labels. 2. The stoichiometry of the reaction with reagent II is reported: 1 mol reagent is bound per mol inactive enzyme. Amino acid analysis of the 6 N HCl hydrolyzate of the inactive enzyme identified CM-histidine as the main alkylation product. This is the first evidence of the presence of a histidine in the active site region. 3. The alkylation rate and involved amino acid residues were studied for both reagents I and II, at pH 8 and 5.5. The particular reactivity of a lysine near or in the active site is discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
