A comparison of ATP-degrading enzyme activities in rat incisor odontoblasts.
In active odontoblasts from the rat incisor, used as a model system for biologic calcification, two distinguishable enzyme activities capable of degrading adenosine monophosphate (ATP) exist. Once can be inhibited ny 1-tetramisole, (+/-)-2,3,5,6,-tetrahydro-6-phenylimidazo (2.1B) THIAZOLE HYDROCHLORIDE (Levamisol) and (+/-)-6(m-bromophenyl)-5.6-dehydroimidazo (2.1-b) thiazole oxalate (R823) and is probably identical with nonspecific alkaline phosphatase (EC 3.1.3.1). The activity of the other enzyme, named Ca2+-ATPase, is dependent on the presence of Ca2+ or Mg2+ and is activated by these ions. The pH optimum of Ca2+-ATPase is 9.8. The Ca2+-ATPase is unaffected by Levamisole, R 8231, ouabain, ruthenium red, Na+ and K+ ions. Maximal activity was found against ATP, whereas adenosine diphosphate, guanosine triphosphate, inosine triphosphate and adensoine monophosphate were hydrolysed at lower rate. It may be speculated that the Ca2+-ATPase is concerned with the transmembranous transport of Ca2+ ions to the mineralization front.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004789:Enzyme Activation; D006863:Hydrogen-Ion Concentration; D007180:Incisor / Q000201:enzymology*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D009804:Odontoblasts / Q000201:enzymology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D012964:Sodium / Q000494:pharmacology
D012964:Sodium; D000469:Alkaline Phosphatase; D000251:Adenosine Triphosphatases; D008274:Magnesium; D011188:Potassium; D002118:Calcium