title: INFLUENCE OF SUBSTRATE-COFACTOR RATIOS ON PARTIALLY PURIFIED INORGANIC PYROPHOSPHATASE ACTIVITY AT ELEVATED TEMPERATURES.
abstract: Mathemeier, Paul F. (Oregon State University, Corvallis), and Richard Y. Morita. Influence of substrate-cofactor ratios on partially purified inorganic pyrophosphatase activity at elevated temperatures. J. Bacteriol. 88:1661-1666. 1964.-Inorganic pyrophosphatase of Bacillus stearothermophilus was studied for optimal substrate-cofactor ratios at 60 to 100 C. Mg(++) was the primary cofactor, and Co(++) resulted in 50% enzyme activity at 60 C. The pH optima differed for the Mg(++) activated and Co(++) activated pyrophosphatase. At 80 C and above, Co(++) replaced Mg(++) as the optimal cofactor in the enzyme reaction. The optimal ratio of pyrophosphate to Mg(++) varied from 2 to 0.25, dependent on enzyme concentration. The optimal pyrophosphate-cobalt ratio was constant at 1.0. The enzyme catalyzed appreciable pyrophosphate hydrolysis at 95 C.
mesh_terms: D001407:Bacillus; D002118:Calcium; D003035:Cobalt; D011756:Diphosphates; D001411:Geobacillus stearothermophilus; D006358:Hot Temperature; D006868:Hydrolysis; D043564:Inorganic Pyrophosphatase; D007700:Kinetics; D008274:Magnesium; D008345:Manganese; D008660:Metabolism; D009922:Oregon; D010600:Pharmacology; D011755:Pyrophosphatases; D012106:Research; D013696:Temperature
chemical_list: D011756:Diphosphates; D003035:Cobalt; D008345:Manganese; C107241:diphosphoric acid; D011755:Pyrophosphatases; D043564:Inorganic Pyrophosphatase; D008274:Magnesium; D002118:Calcium
keywords: BACILLUS; CALCIUM; COBALT; EXPERIMENTAL LAB STUDY; HEAT; KINETICS; MAGNESIUM; MANGANESE; METABOLISM; PHARMACOLOGY; PYROPHOSPHATASE