Nakamura Shoji, Yamashita Ryohei, Miyauchi Yuu, Tanaka Yoshitaka, Ishii Yuji
Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
Xenobiotica. 2021 Nov;51(11):1247-1254. doi: 10.1080/00498254.2021.2001075. Epub 2021 Nov 11.
Adenine-related compounds are allosteric inhibitors of UDP-glucuronosyltransferase (UGT) in rat liver microsomes (RLM) and human UGT isoforms treated with detergent or pore-forming peptide, alamethicin.To clarify whether the same is true beyond species, the effects of adenine-related compounds on 4-methylumbelliferone (4-MU) glucuronidation were examined using detergent-treated mouse liver microsomes (MLM).Brij-58 treatment of MLM increased the and the Michaelis constant, of 4-MU. This study was performed using Brij-58-treated MLM as an enzyme source. ATP- and ADP-inhibited 4-MU glucuronidation. In contrast, AMP caused a 1.5-fold increase in glucuronidation. Oxidised forms, NAD and NADP, potently inhibited 4-MU glucuronidation, whereas the reduced forms, NADH and NADPH, did not. Furthermore, the IC values of ATP, ADP, NAD, and NADP were approximately 15 μM.In our previous study, ATP was the strongest inhibitor of UGT activity in RLM. However, in this study, the above-mentioned compounds inhibited 4-MU UGT in a comparable and non-competitive manner. Furthermore, AMP antagonised the inhibitory effects of ATP and ADP.These results suggest that ATP, ADP, NAD, and NADP are common endogenous inhibitors of UGT beyond species.
腺嘌呤相关化合物是大鼠肝微粒体（RLM）以及用去污剂或成孔肽阿拉霉素处理的人UGT同工型中UDP-葡萄糖醛酸基转移酶（UGT）的变构抑制剂。为了阐明在不同物种中情况是否相同，使用经去污剂处理的小鼠肝微粒体（MLM）研究了腺嘌呤相关化合物对4-甲基伞形酮（4-MU）葡萄糖醛酸化的影响。用Brij-58处理MLM可提高4-MU的 以及米氏常数 。本研究使用经Brij-58处理的MLM作为酶源。ATP和ADP抑制4-MU葡萄糖醛酸化。相反，AMP使葡萄糖醛酸化增加了1.5倍。氧化形式的NAD和NADP强烈抑制4-MU葡萄糖醛酸化，而还原形式的NADH和NADPH则无此作用。此外，ATP、ADP、NAD和NADP的IC值约为15μM。在我们之前的研究中，ATP是RLM中UGT活性的最强抑制剂。然而，在本研究中，上述化合物以类似且非竞争性的方式抑制4-MU UGT。此外，AMP拮抗ATP和ADP的抑制作用。这些结果表明，ATP、ADP、NAD和NADP是不同物种中UGT常见的内源性抑制剂。
