The effects of cadmium on the p-nitrophenyl phosphatase and inorganic pyrophosphatase activities of alkaline phosphatase in developing hamster tooth germs.
p-Nitrophenyl phosphatase (p-NPP-ase) and inorganic pyrophosphatase (PPi-ase) activities originate from the same alkaline phosphatase enzyme. Only the PPi-ase site has zinc (Zn2+) as a cofactor. Cadmium (Cd2+) in concentrations from 10(-5) mol/l upwards inhibited the PPi-ase activity, but did not inhibit the p-NPP-ase activity at all. In mineralizing tooth germs Cd2+ may replace Zn2+, thereby changing the specific stereoconfiguration in the active centre needed for PPi-ase activity, but not that for p-NPP-ase activity.
Wöltgens
J H
JH
Department of Oral Cell Biology, Academic Center for Dentistry, Amsterdam, The Netherlands.
Bervoets
T J
TJ
Lyaruu
D M
DM
Bronckers
A L
AL
D009597:4-Nitrophenylphosphatase / Q000378:metabolism*; D000818:Animals; D002104:Cadmium / Q000494:pharmacology*; D006224:Cricetinae; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D011755:Pyrophosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014083:Tooth Germ / Q000187:drug effects / Q000201:enzymology*; D015032:Zinc / Q000378:metabolism
D002104:Cadmium; D010744:Phosphoric Monoester Hydrolases; D009597:4-Nitrophenylphosphatase; D011755:Pyrophosphatases; D015032:Zinc