Biochemistry of coenzyme B12-dependent glycerol and diol dehydratases and organization of the encoding genes

作者：Rolf Daniel, Thomas A. Bobik, Gerhard Gottschalk · 发表于：FEMS Microbiology Reviews · 年份：1998 · DOI：10.1111/j.1574-6976.1998.tb00387.x · 被引用次数：137 · 研究领域：Porphyrin Metabolism and Disorders、Folate and B Vitamins Research、Iron Metabolism and Disorders

Glycerol and diol dehydratases exhibit a subunit composition of alpha 2 beta 2 gamma 2 and contain coenzyme B12 in the base-on form. The dehydratase reaction proceeds via a radical mechanism. The dehydratases are subject to reaction inactivation by the substrate glycerol which is caused by a cessation of the catalytic cycle because coenzyme B12 is not regenerated, instead 5'-deoxyadenosine and a catalytically inactive cobalamin are formed. The genetic organization of the dehydratase genes is quite similar in all organisms. Downstream of the dehydratase genes an open reading frame encoding a polypeptide of approximately 600 amino acids was identified which is apparently involved in the reactivation of suicide-inactivated enzyme.