Martens J H, Barg H, Warren M J, Jahn D
Institute for Microbiology, Technical University Braunschweig, Germany.
Appl Microbiol Biotechnol. 2002 Mar;58(3):275-85. doi: 10.1007/s00253-001-0902-7. Epub 2001 Dec 20.
One of the most alluring and fascinating molecules in the world of science and medicine is vitamin B12 (cobalamin), which was originally discovered as the anti pernicious anemia factor and whose enigmatic complex structure is matched only by the beguiling chemistry that it mediates. The biosynthesis of this essential nutrient is intricate, involved and, remarkably, confined to certain members of the prokaryotic world, seemingly never have to have made the eukaryotic transition. In humans, the vitamin is required in trace amounts (approximately 1 microg/day) to assist the actions of only two enzymes, methionine synthase and (R)-methylmalonyl-CoA mutase; yet commercially more than 10 t of B12 are produced each year from a number of bacterial species. The rich scientific history of vitamin B12 research, its biological functions and the pathways employed by bacteria for its de novo synthesis are described. Current strategies for the improvement of vitamin B12 production using modern biotechnological techniques are outlined.
维生素B12（钴胺素）是科学和医学领域中最具吸引力和魅力的分子之一。它最初是作为抗恶性贫血因子被发现的，其神秘复杂的结构只有它所介导的迷人化学反应能与之相匹配。这种必需营养素的生物合成过程错综复杂，而且显著的是，它仅限于原核生物界的某些成员，似乎从未经历过向真核生物的转变。在人类中，这种维生素只需微量（约1微克/天）就能协助仅有的两种酶，即甲硫氨酸合酶和（R）-甲基丙二酰辅酶A变位酶发挥作用；然而，每年从多种细菌中商业生产的B12超过10吨。本文描述了维生素B12研究丰富的科学历史、其生物学功能以及细菌用于从头合成它的途径。概述了目前使用现代生物技术提高维生素B12产量的策略。
