Hallinan T, Pohl K R, de Brito R
Med Biol. 1979 Oct;57(5):269-73.
The ability of five nucleotides in the presence of excess divalent cations to inhibit UDPglucuronosyltransferase in sealed or leaky liver microsomal vesicles was studied. Two nucleotides inhibited potently while three others were weak inhibitors. At low concentration, both of the potent inhibitors, uridine tri- and diphosphates tended to inhibit more in sealed microsomal vesicles than in leaky microsomes, while the weak inhibitors, uridine diphosphate glucose and adenosine triphosphate behaved in the opposite manner and inhibited less in sealed than in leaky microsomes. At physiological concentrations of UDPglucuronic acid (0.4 mM) quite extensive inhibition of oestradiol glucuronidation could be achieved with physiological concentrations of uridine tri- or diphosphates (0.2 or 0.4 mM). In sealed or leaky microsomes, beta, gamma-methylene-interrupted uridine triphosphate, which is resistant to hydrolysis by nucleoside triphosphatase, inhibited much less than did uridine triphosphate.
研究了在存在过量二价阳离子的情况下，五种核苷酸抑制密封或有渗漏的肝微粒体囊泡中尿苷二磷酸葡萄糖醛酸转移酶的能力。两种核苷酸有强效抑制作用，另外三种则是弱抑制剂。在低浓度时，两种强效抑制剂，即三磷酸尿苷和二磷酸尿苷，在密封的微粒体囊泡中比在有渗漏的微粒体中倾向于产生更强的抑制作用，而弱抑制剂，即二磷酸尿苷葡萄糖和三磷酸腺苷的表现则相反，在密封的微粒体中比在有渗漏的微粒体中抑制作用更小。在生理浓度的尿苷二磷酸葡萄糖醛酸（0.4 mM）下，生理浓度的三磷酸尿苷或二磷酸尿苷（0.2或0.4 mM）可对雌二醇葡萄糖醛酸化产生相当广泛的抑制作用。在密封或有渗漏的微粒体中，对核苷三磷酸酶水解有抗性的β,γ-亚甲基间断三磷酸尿苷的抑制作用远小于三磷酸尿苷。
