Ziganshin A U, Ziganshina L E, Bodin P, Bailey D, Burnstock G
Department of Anatomy and Developmental Biology, University College London, UK.
Biochem Mol Biol Int. 1995 Jul;36(4):863-9.
Ecto-nucleotidase activity was studied on primary cultures of guinea-pig vas deferens smooth muscle cells by measuring the inorganic phosphate (Pi) production using ATP as a substrate. The ecto-nucleotidase was insensitive to ouabain, oligomycin, sodium azide, p-nitrophenyl phosphate and B-glycerophosphate. Enzyme activity was highly dependent on either Ca2+ or Mg2+. Antagonists of P2X-purinoceptors, pyridoxalphosphate-6-azophenyl-2',4'- disulphonic acid, 4'4'-diisothiocyanatostilbene-2'2'- disulphonate, suramin and pyridoxal-5-phosphate, significantly inhibited ecto-nucleotidase activity. In contrast, the P1-purinoceptor antagonists, 8-p-sulphophenyl theophylline and 1,3-dipropyl-8-cyclopentylxanthine, did not affect the enzyme activity. Thus, when P2-purinoceptors are studied by testing agonists and antagonists potencies, the inhibition of ecto-nucleotidase activity by currently available P2-purinoceptor antagonists should be taken into account.
通过以三磷酸腺苷（ATP）为底物测量无机磷酸盐（Pi）的生成，研究了豚鼠输精管平滑肌细胞原代培养物中的外切核苷酸酶活性。外切核苷酸酶对哇巴因、寡霉素、叠氮化钠、对硝基苯磷酸酯和β-甘油磷酸酯不敏感。酶活性高度依赖于Ca2+或Mg2+。P2X嘌呤受体拮抗剂，磷酸吡哆醛-6-偶氮苯-2',4'-二磺酸、4',4'-二异硫氰酸根合芪-2',2'-二磺酸、苏拉明和磷酸吡哆醛-5-磷酸，显著抑制外切核苷酸酶活性。相比之下，P1嘌呤受体拮抗剂，8-对磺基苯基茶碱和1,3-二丙基-8-环戊基黄嘌呤，不影响酶活性。因此，在用激动剂和拮抗剂效价测试研究P2嘌呤受体时，应考虑到目前可用的P2嘌呤受体拮抗剂对外切核苷酸酶活性的抑制作用。
