Sauer F D
Animal Research Centre, Agriculture Canada, Ottawa, Ontario.
Biochem Biophys Res Commun. 1991 Jan 31;174(2):619-24. doi: 10.1016/0006-291x(91)91462-l.
Uridine-5'-diphospho-N-acetylglucosamine, when oxidized with periodate to the corresponding aldehyde (o-UDP-GlcNAc), was a potent inhibitor of the methylcoenzyme M methylreductase reaction which catalyzes the reductive demethylation of methylcoenzyme M to methane. The oxidation product, o-UDP-GlcNAc, appears to bind to the UDP-GlcNAc site of the enzyme and inhibits the reduction of methylcoenzyme M both by MRF or its active hydrolytic fragment HS-HTP. The kinetic patterns indicate that o-UDP-GlcNAc inhibition is noncompetitive with HS-HTP or MRF, and the Hill coefficient indicated that there was cooperativity between the UDP and HS-HTP binding sites. The methylreductase enzyme was protected from o-UDP-GlcNAc inhibition by prior exposure to low concentrations of MRF. HS-HTP, at the same concentration as MRF, was not effective in protecting the enzyme from inhibition by o-UDP-GlcNAc.
尿苷-5'-二磷酸-N-乙酰葡糖胺经高碘酸盐氧化生成相应的醛（o-UDP-GlcNAc）后，是甲基辅酶M甲基还原酶反应的有效抑制剂，该反应催化甲基辅酶M还原脱甲基生成甲烷。氧化产物o-UDP-GlcNAc似乎与该酶的UDP-GlcNAc位点结合，并抑制MRF或其活性水解片段HS-HTP对甲基辅酶M的还原作用。动力学模式表明，o-UDP-GlcNAc抑制作用与HS-HTP或MRF无竞争性，希尔系数表明UDP和HS-HTP结合位点之间存在协同作用。预先暴露于低浓度的MRF可保护甲基还原酶免受o-UDP-GlcNAc的抑制。与MRF浓度相同的HS-HTP在保护该酶免受o-UDP-GlcNAc抑制方面无效。
