Studies on ATP hydrolysis in medium for histochemical demonstration of ATPase activity

Summary Nonenzymatic ATP hydrolysis in medium of Wachstein and Meisel for histochemical demonstration of ATPase activity was investigated. In this medium considerable amounts of phosphorus are released without the participation of the enzyme. ATP hydrolysis in Wachstein-Meisel's medium increase with the concentration of Pb⁺⁺ and decrease at its small concentrations. The degree of ATP hydrolysis appeared to increase with increase both temperature and pH. At high concentration of ATP (5.76 mM) the degree of ATP hydrolysis in Wachstein-Meisel's medium is lower than at 1.44 mM ATP. 10.0 mM Ca⁺⁺ or 3.6 mM Fe⁺⁺ speed up ATP hydrolysis after 30- and 60-minute incubation. In the presence of 3.6 mM Co⁺⁺ or 2.6 mM Cu⁺⁺ ATP hydrolysis in Wachstein-Meisel's medium increased throughout the whole period examined. On the contrary, 3.6 mM Fe⁺⁺⁺ decreases ATP hydrolysis in this medium.10.0 mM F^– raises the degree of ATP hydrolysis which is, however, lowered in the presence of 2.5 mM pCMB or 3.6 mM KCN. 2.0 mM cysteine highly inhibits the process of nonenzymatic ATP hydrolysis in Wachstein-Meisel's medium.These data show that the histochemical reaction for ATPase activity in Wachstein-Meisel's medium does not originate exclusively from the hydrolysis of ATP in the presence of Pb⁺⁺, but take rise, above all, as a result of an enzymatic reaction.