Characterization of Vitamin B12 Compounds in Fermented Poultry Manure Fertilizers

(1) Background: Currently, no data are available on the vitamin B12 content of an organic fertilizer product, viz. fermented poultry manure, or whether the organic fertilizer product contains vitamin B12 or inactive corrinoids (or both). (2) Methods: This study conducted a microbiological assay to determine the vitamin B12 content of various commercially available fermented poultry manure fertilizer products. (3) Results: The results varied from 1.4 μg to approximately 20 μg per 100 g of dry weight. In the bioautography analysis, selected products had two positive spots with identical Rf values of vitamin B12 and pseudovitamin B12. High-performance liquid chromatography and liquid chromatography/electrospray ionization−mass spectrometry analyses of the selected products indicated that these fertilizers primarily contained vitamin B12. They also contained minor inactive cobamides such as pseudovitamin B12, 2-methyladenyl cobamide, and 2-methylmercaptoadenyl cobamide. (4) Conclusions: These results suggested that edible plants would enrich vitamin B12 using fermented poultry manure organic fertilizer products.

Biological Activity of Pseudovitamin B12 on Cobalamin-Dependent Methylmalonyl-CoA Mutase and Methionine Synthase in Mammalian Cultured COS-7 Cells

Adenyl cobamide (commonly known as pseudovitamin B12) is synthesized by intestinal bacteria or ingested from edible cyanobacteria. The effect of pseudovitamin B12 on the activities of cobalamin-dependent enzymes in mammalian cells has not been studied well. This study was conducted to investigate the effects of pseudovitamin B12 on the activities of the mammalian vitamin B12-dependent enzymes methionine synthase and methylmalonyl-CoA mutase in cultured mammalian COS-7 cells to determine whether pseudovitamin B12 functions as an inhibitor or a cofactor of these enzymes. Although the hydoroxo form of pseudovitamin B12 functions as a coenzyme for methionine synthase in cultured cells, pseudovitamin B12 does not activate the translation of methionine synthase, unlike the hydroxo form of vitamin B12 does. In the second enzymatic reaction, the adenosyl form of pseudovitamin B12 did not function as a coenzyme or an inhibitor of methylmalonyl-CoA mutase. Experiments on the cellular uptake were conducted with human transcobalamin II and suggested that treatment with a substantial amount of pseudovitamin B12 might inhibit transcobalamin II-mediated absorption of a physiological trace concentration of vitamin B12 present in the medium.

Native Corrinoids from Clostridium cochlearium Are Adeninylcobamides: Spectroscopic Analysis and Identification of Pseudovitamin B12 and Factor A

ABSTRACT The corrinoids from the obligate anaerobe Clostridium cochlearium were extracted as a mixture of Coβ-cyano derivatives. From 50 g of frozen cells, approximately 2 mg (1.5 μmol) of B12 derivatives was obtained as a crystalline sample. Analysis of the corrinoid sample ofC. cochlearium by a combination of high-pressure liquid chromatography and UV-Vis absorbance spectroscopy revealed the presence of three cyano corrinoids in a ratio of about 3:1:1. The spectroscopic data acquired for the sample indicated the main components to be pseudovitamin B12(Coβ-cyano-7"-adeninylcobamide) (60%) and factor A (Coβ-cyano-7"-[2-methyl]adeninylcobamide) (20%). Authentic pseudovitamin B12 was prepared by guided biosynthesis from cobinamide and adenine. Both pseudovitamin B12 and its homologue, factor A, were subjected to complete spectroscopic analysis by UV-Vis, circular dichroism, mass spectrometry, and by one- and two-dimensional 1H,13C-, and 15N nuclear magnetic resonance (NMR) spectroscopy. The third component was indicated by the mass spectra to be an isomer of factor A and is likely (according to NMR) to be 7"-[N 6-methyl]-adeninylcobamide, a previously unknown corrinoid. C. cochlearium thus biosynthesizes as its native “complete” B12 cofactors the 7"-adeninylcobamides and two homologous corrinoids, in which the nucleotide base is a methylated adenine.