Fischer Markus, Bacher Adelbert
Lehrstuhl für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstr. 4, D-85747, Garching, Germany.
Nat Prod Rep. 2005 Jun;22(3):324-50. doi: 10.1039/b210142b. Epub 2005 Apr 21.
The biosynthesis of one riboflavin molecule requires one molecule of GTP and two molecules of ribulose 5-phosphate. The imidazole ring of GTP is hydrolytically opened, yielding a 2,5-diaminopyrimidine that is converted to 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione by a sequence of deamination, side chain reduction, and dephosphorylation. Condensation of 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione with 3,4-dihydroxy-2-butanone 4-phosphate obtained from ribulose 5-phosphate affords 6,7-dimethyl-8-ribityllumazine. Dismutation of the lumazine derivative yields riboflavin and 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione, which is recycled in the biosynthetic pathway. The enzymes of the riboflavin pathway are potential targets for antibacterial agents.
一个核黄素分子的生物合成需要一分子鸟苷三磷酸（GTP）和两分子5-磷酸核酮糖。GTP的咪唑环通过水解打开，产生一个2,5-二氨基嘧啶，该嘧啶通过一系列脱氨基、侧链还原和去磷酸化反应转化为5-氨基-6-核糖基氨基-2,4(1H,3H)-嘧啶二酮。5-氨基-6-核糖基氨基-2,4(1H,3H)-嘧啶二酮与从5-磷酸核酮糖获得的3,4-二羟基-2-丁酮4-磷酸缩合，生成6,7-二甲基-8-核糖基卢马嗪。卢马嗪衍生物的歧化反应产生核黄素和5-氨基-6-核糖基氨基-2,4(1H,3H)-嘧啶二酮，后者在生物合成途径中循环利用。核黄素途径的酶是抗菌剂的潜在作用靶点。
