Kolonko B, Hörig J A, Renz P
Institut für Biologische Chemie und Ernährungswissenschaft Universität Hohenheim, Stuttgart, Bundesrepublik Deutschland.
Z Naturforsch C J Biosci. 1992 Mar-Apr;47(3-4):171-6. doi: 10.1515/znc-1992-3-401.
The 5,6-dimethylbenzimidazole unit of vitamin B12 is formed from riboflavin via FMN in aerobic and some aerotolerant bacteria. Thereby C-1' of the ribityl side chain gets C-2 of 5,6-dimethylbenzimidazole. Experiments with homogenates of Propionibacterium shermanii on the fate of C-atoms 2' to 5' of the ribityl side chain of riboflavin in this transformation are reported. It was found that [5'-3H]riboflavin leads to radioactive sugar phosphates. These were isolated, dephosphorylated, and separated. Thus 3H-D-fructose and 3H-D-glucose were detected. The degradation of 3H-D-glucose revealed that 14 per cent of the total radioactivity was located in C-1, and 86 per cent in C-6. This indicates that during 5,6-dimethylbenzimidazole biosynthesis a three carbon unit is formed from the ribityl side chain of riboflavin.
在需氧和一些耐氧细菌中，维生素B12的5,6-二甲基苯并咪唑单元由核黄素经黄素单核苷酸形成。由此，核糖醇侧链的C-1'得到5,6-二甲基苯并咪唑的C-2。报道了关于谢氏丙酸杆菌匀浆在这种转化中核黄素核糖醇侧链C-2'至C-5'碳原子命运的实验。发现[5'-3H]核黄素会产生放射性糖磷酸酯。这些被分离、去磷酸化并分开。由此检测到3H-D-果糖和3H-D-葡萄糖。3H-D-葡萄糖的降解表明，总放射性的14%位于C-1，86%位于C-6。这表明在5,6-二甲基苯并咪唑生物合成过程中，一个三碳单元由核黄素的核糖醇侧链形成。
