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Inhibition of adenylate cyclase by the 2,3-dialdehyde of adenosine triphosphate
Inhibition of adenylate cyclase by the 2',3'-dialdehyde of adenosine triphosphate.
30
The periodate-oxidized analog of ATP, 2',3'-dialATP, competitively inhibited bovine brain and rat liver adenylate cyclase. The apparent Ki for inhibition of brain adenylate cyclase by 2',3'-dialATP was 196 microM in the presence of Mg2+ and 37 microM in the presence of Mn2+. The Ki values for inhibition of rat liver adenylate cyclase by 2',3'-dialATP were 48 and 30 microM in the presence of Mg2+; and Mn2+, respectively. Adenylate cyclase activity was irreversibly inactivated by 2'3'-dialATP in the presence of NaCNBH3 and the kinetics for loss in enzyme activity were pseudo-first order. Both ATP and Tris protected adenylate cyclase from irreversible inhibition by 2',3'-dialATP and NaCNBH3. It is proposed that 2',3'-dialATP forms a Schiff's base with an amino group at the active site of the enzyme and that Na-CNBH3 reduction of this Schiff's base causes irreversible modification of the catalytic subunit. The Km for 2',3'-dialATP inactivation, the maximal rate constant of inactivation, and protection of the enzyme by ATP were not affected by the presence or absence of free Mg2+. These data indicate that a divalent cation is not required for binding of 2',3'-dialATP to the active site of adenylate cyclase.
Westcott KR, Olwin BB, Storm DR
The Journal of biological chemistry
1980-09-25 00:00
255
18
8767-71
Adenosine Triphosphate,Adenylate Cyclase,Animals,Cattle,Cell Membrane,Cerebral Cortex,Edetic Acid,Kinetics,Liver,Magnesium,Manganese,Protein Binding,Rats,2',3'-dialdehyde ATP,Adenosine Triphosphate,Edetic Acid,Magnesium,Manganese,Adenylate Cyclase
J. Biol. Chem.
NHLBI HL-23606, NIAID K04 AI00310
0021-9258
877
True
6773947
