Synthesis, Structures, And Properties Of Coenzyme B₁₂ Models And Analogue

Coenzyme B12 (5'-deoxyadenosylcobalamin, AdoCbl) is one of the known organometallic complexes in nature. It serves as a cofactor for various enzymatic reactions. A common feature of these reactions is the 1,2-interchange of a hydrogen atom and another substituent on adjacent carbon atoms of the substrate. One of the key steps in those enzymatic reactions is that the distortion of corrin ring of the cofactor is induced by enzyme-proteins, and then the cobalt-carbon bond is broken to produce a 5'-deoxyadenosyl radical and B12r. Therefore, encompassing the formation and decomposition of the cobalt-carbon bond, a large number of coenzyme B12 models and analogues have been prepared and efforts have been made for investigation in detail on their mechanism, kinetics, bond dissociation energy (BDE), electrochemical property and action in coenzyme B12 dependent enzymatic reaction during Co-C bond cleavage. Though long history relevant to the chemistry, biology, and medicine of B12 has passed away, recent years have seen an upsurge in activity in many areas due to several recent developments. For example, there has been much interest in bioconjugates of B12 as diagnostic and therapeutic agents. By absorbing and conveying of B12, the corrin ring or chemical modified B12 derivative acts as the carrier of medicament and diagnostic. Biochemistry study of B12 has been extended from initial mutase to other primal bacteriase. Cobalamin has been bonded to cyclodextrin or crown ether to model B12 holoenzyme. Besides, B12 and B12...