Bicarbonate-stimulated ATPase activity of bovine liver alkaline phosphatase.
A commercial preparation of bovine hepatic alkaline phosphatase was found to have a Mg2+-stimulated ATPase activity. The pH optimum was 8.5, the Km for ATP was 4.2 X 10(-5) M and the Vmax was 88.3 mumol Pi . h-1 . mg-1. HCO3- had a stimulatory effect on Mg2+ -ATPase activity. Other anions had no effect or an inhibitory effect while Na+, K+ and ouabain had no effect. Purification of the commercial preparation by gel filtration and affinity chromatography yielded a fraction with alkaline phosphatase and (Mg2+ + HCO3-)ATPase activities that had been enriched respectively 27-fold and 23-fold; both activities were inhibited by levamisole (93.1% and 93.8%, respectively) and the purified fraction was found to be a single protein on sodium dodecyl sulfate polyacrylamide gel electrophoresis. These results suggest that alkaline phosphatase and (Mg2+ + HCO3-)ATPase may be properties of the same liver protein that might be involved in biliary HCO3- transport and bile secretion.
Corbic
M
M
de Couët
G
G
Bertrand
O
O
Cochet
S
S
Erlinger
S
S
D000469:Alkaline Phosphatase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology*; D001647:Bile Acids and Salts / Q000494:pharmacology; D017301:Ca(2+) Mg(2+)-ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002417:Cattle; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D006709:Homoarginine / Q000494:pharmacology; D007700:Kinetics; D007978:Levamisole / Q000494:pharmacology; D008099:Liver / Q000201:enzymology*; D010042:Ouabain / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology
D001639:Bicarbonates; D001647:Bile Acids and Salts; D006709:Homoarginine; D007978:Levamisole; D010042:Ouabain; D012964:Sodium; D000469:Alkaline Phosphatase; D017301:Ca(2+) Mg(2+)-ATPase