Modification of the catalytic and regulatory properties of beef heart AMP-deaminase by DTNB treatment.
In beef heart AMP-deaminase (EC 3.5.4.6.), 7 SH-groups out of 26 half-cysteine residues in the protein molecule have been shown to be accessible to alkylation by DTNB in the absence of ATP. The addition of ATP showed that only 6 SH-groups were accessible. DTNB-modified enzyme showed about 30% of the native catalytic activity but no sensitivity to the ATP-activating effect. Almost full reactivation of the modified enzyme and the restoration of the activatory effect of ATP could be achieved by exhaustive dialysis against mercaptoethanol.
D000659:AMP Deaminase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000494:Allosteric Regulation; D000818:Animals; D002417:Cattle; D003545:Cysteine; D004228:Dithionitrobenzoic Acid / Q000494:pharmacology; D009206:Myocardium / Q000201:enzymology*; D009709:Nucleotide Deaminases / Q000378:metabolism*; D010084:Oxidation-Reduction; D011487:Protein Conformation
D004228:Dithionitrobenzoic Acid; D009709:Nucleotide Deaminases; D000659:AMP Deaminase; D003545:Cysteine