Lactobacilli cobalamin

Taranto, M. R, Vera, J. L., Hugenholtz, J., de Valdez, G. R, Sesma, P. (2003). Lactobacillus reuteri CRL1098 produces Cobalamin. Journal of Bacteriology, 185, 5643-5647. 

The reductase of Lactobacillus leichmamii has also been extensively studied. It differs from the E. coli enzyme in that it requires cobalamin as a coenzyme and uses nucleoside triphosphates, rather than diphosphates, as substrates [7,139]. The enzyme also shows allosteric properties which are governed by nucleoside triphosphates as effectors. The interpretation of these effects and analysis of kinetic data are complicated by the fact that the modifiers are also substrates and products, and that their effects are profoundly influenced by ionic strength and concentrations. 

In 2002, Sato and co-workers replaced IF with vitamin Bi2-targeting Lactobacillus helveticus B-1 in the vitamin Bn assay by CL method due to its cost and non-availability (Sato et al. 2002). Lactobacillus helveticus B-1 is assumed to have a vitamin Bn targeting (or binding) site on its cells and binds vitamin Bn instantly and quantitatively. This reaction is specific to complete vitamin Bn compounds, cobalamins, and was used for a vitamin Bn assay method by CL. The calibration graph was linear from 0.1 to 10 ng/mL. 

Cyanocobalamin (Formula 6.17) was isolated in 1948 from Lactobacillus lactis. Due to its stability and availability, it is the form in which the vitamin is used most often. In fact, cyanocobalamin is formed as an artifact in the processing of biological materials. Cobalamins occur naturally as adenosylcobalamin and methylcobalamin, which instead of the cyano group contain a 5 -deoxyadenosyl residue and a methyl group respectively. 

Morita, H., Toh, H., Fukuda, S., et al. (2008). Comparative genome analysis of Lactobacillus reuteri and Lactobacillus fermentum reveal a genomic island for reuterin and cobalamin production. DNA Res 15,151-161. 

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