Characterization of the inhibition of rabbit muscle adenylate kinase by fluoride and beryllium ions.
In the presence of NaF, BeCl2, ADP, and Mg2+, rabbit muscle adenylate kinase was strongly inhibited. Molecules responsible for the inhibition were identified after subjecting the inhibited enzyme to filtration-centrifugation through small Sephadex G-50 columns. Full inhibition was correlated with the entrapment of 2 mol of ADP, 1 mol of beryllium, and 1 mol of magnesium per mole of enzyme; when an excess of AMP was present together with ADP, only 1 mol of bound ADP was detected in the desalted inhibited enzyme, due to the release of a loosely bound AMP. The fluorometal species identified in the ADP-fluoroberyllate entrapped complex were BeF+, BeF2, and BeF3-. When inhibited adenylate kinase was diluted in a medium deprived of the inhibitory species, the enzyme activity was progressively recovered, and a k(off) value of 0.23 min-1 for the release of the inhibitor complex was calculated. The possibility that the inhibitory nucleotide-fluoroberyllate complex behaves as a transition-state analog is discussed.
Garin
J
J
Département de Biologie Moléculaire et Structurale, Groupement CEA-CNRS-INSERM-UJF, Centre d'Etudes Nucléaires de Grenoble, France.
Vignais
P V
PV
D000244:Adenosine Diphosphate / Q000378:metabolism / Q000494:pharmacology; D000263:Adenylate Kinase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000818:Animals; D000838:Anions; D001608:Beryllium / Q000494:pharmacology*; D002412:Cations; D005459:Fluorides / Q000494:pharmacology*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D009132:Muscles / Q000201:enzymology*; D011817:Rabbits; D012964:Sodium / Q000378:metabolism
D000838:Anions; D002412:Cations; D000244:Adenosine Diphosphate; D012964:Sodium; D000263:Adenylate Kinase; D008274:Magnesium; D001608:Beryllium; D005459:Fluorides