Hydrolysis of extracellular adenine nucleotides by cultured bovine endocardial endothelial cells.
OBJECTIVE
To characterize the ATP diphosphohydrolase (apyrase) of bovine endocardial endothelial cells, and to compare ecto-adeninenucleotidase activity between bovine endocardial and aortic endothelial cells (BEEC and BAEC).


METHODS
The nucleotide was analyzed by reversed phase HPLC and apyrase activity was assayed by inorganic phosphate release.


RESULTS
Apyrase inhibitors, both NaN3 10 mmol.L-1 and NaF 20 mmol.L-1, inhibited BEEC apyrase activity by 51% and 38%, respectively. The inhibitor for Na+/K(+)-ATPase, ouabain, did not affect the enzyme activity. Edetic acid 5 mmol.L-1 completely inhibited the enzyme activity. H2O2 0.5 mmol.L-1 downregulated BEEC apyrase activity in a time-dependent manner. The apyrases activities in BAEC were higher than those in BEEC, while the ecto-AMPase activity in BAEC was much weaker than that in BEEC.


CONCLUSIONS
BEEC have NaN3- and NaF-sensitive, ouabain-insensitive apyrase activity. BEEC had high ecto-AMPase activities, and low apyrases activities as compared with BAEC.
Yi
F X
FX
Laboratory of Molecular Pharmacology, Hunan Medical University, Changsha, China.
Liu
W L
WL
Chen
L W
LW
Zeng
S
S
Guo
Z G
ZG
D000818:Animals; D001011:Aorta; D001081:Apyrase / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D004699:Endocardium / Q000166:cytology / Q000201:enzymology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D006868:Hydrolysis; D009708:Nucleotidases / Q000378:metabolism; D010042:Ouabain / Q000494:pharmacology; D019810:Sodium Azide / Q000494:pharmacology; D012969:Sodium Fluoride / Q000494:pharmacology
D004791:Enzyme Inhibitors; D010042:Ouabain; D012969:Sodium Fluoride; D019810:Sodium Azide; D006861:Hydrogen Peroxide; D009708:Nucleotidases; C018775:adenosine monophosphatase; D001081:Apyrase