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Effects of lead acetate on rat brain K sup + -paranitrophenyl phosphatase (K-PNPPASE)

Journal Article · · FASEB Journal (Federation of American Societies for Experimental Biology); (USA)
OSTI ID:7190496
Lead (Pb) inhibited K-PNPPASE of rat brain P{sub 2} fraction in a concentration dependent manner with median inhibitory concentration of 3.5 {times} 10{sup {minus}6M}. Altered pH versus activity demonstrated comparable inhibitions by Pb in buffered acidic, neutral and alkaline pH ranges. Inhibition of enzyme activity was decreased with increase in temperature (17-27-37{degree}C) suggesting negative correlation. Sulfhydryl agents such as cysteine dithiothreitol (DTT) but not glutathione protected Pb inhibition. Kinetic studies on cationic-substrate activation with Pb alone, Pb + cysteine and Pb + DTT showed significant changes in kinetic constants (K{sub m} and V{sub max}). These results confirmed that Pb inhibits Na{sup +}-K{sup +} ATPase system by interacting with dephosphorylation of the enzyme-phosphoryl complex and exerts and effect similar to that of SH-blocking agents.
OSTI ID:
7190496
Journal Information:
FASEB Journal (Federation of American Societies for Experimental Biology); (USA), Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (USA) Vol. 3:3; ISSN FAJOE; ISSN 0892-6638
Country of Publication:
United States
Language:
English