The deposition of calcium pyrophosphate by NTP pyrophosphohydrolase of matrix vesicles from fetal bovine epiphyseal cartilage.
About 5 mumol CaPPi/mg protein was deposited within 3 h in the presence of the reaction mixtures containing 1 mM ATP, 2 mM Ca2+, 1 mM Pi, and 17 micrograms of purified NTP pyrophosphohydrolase. At 1 mM ATP, 50% of the deposition was inhibited by 0.5-1 mM of various substrate and product analogues including AMP, ADP, and ethylene hydroxyl diphosphonate. The magnitude of inhibition on NTP pyrophosphohydrolase activity was in the order of AMP = CMP = ADP greater than adenosine greater than adenine greater than NAD = NADP. AMP, CMP, ADP, and adenosine are competitive inhibitors. The modes of inhibition by adenine, NAD, and NADP differ from the competitive inhibition. Ribose, 3'-AMP, 2'-AMP, and cAMP did not inhibit the enzyme activity.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001857:Bone Matrix / Q000196:embryology / Q000201:enzymology*; D002131:Calcium Pyrophosphate / Q000378:metabolism*; D002132:Calcium Radioisotopes; D002417:Cattle; D011756:Diphosphates / Q000378:metabolism*; D005333:Fetus; D006132:Growth Plate / Q000196:embryology / Q000201:enzymology*; D007700:Kinetics; D010761:Phosphorus Radioisotopes; D011755:Pyrophosphatases / Q000378:metabolism*; D012265:Ribonucleotides / Q000494:pharmacology
D002132:Calcium Radioisotopes; D011756:Diphosphates; D010761:Phosphorus Radioisotopes; D012265:Ribonucleotides; D000255:Adenosine Triphosphate; D011755:Pyrophosphatases; C021895:nucleoside triphosphate pyrophosphatase; D002131:Calcium Pyrophosphate