THE INFLUENCE OF VITAMIN B12 ON THE BIOSYNTHESIS OF THE METHYL GROUP OF CHOLINE FROM METHANOL

Through the dry period to early lactation the cow goes through a dramatic change in her metabolism. To supply the high energy requirement in early lactation fat supply from the diet and body mobilisation increases substantially. As a result, the liver accumulates fat, the rate of detoxification slows down, ammonia accumulates and there’s a reduced supply of fat, glucose and protein to the udder. This trial was designed to evaluate the response of dairy cows to product called ABN-LiFT a proprietary mixture of B-group vitamins and methyl group donors (rumen protected choline, niacin, vitamin B12, biotin, folic acid and thiamine) designed to reduce the accumulation of triglycerides in the liver and accelerate VLDL export.

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The Effect of Vitamin B12 Deficiency on Methylfolate Metabolism and Pteroylpolyglutamate Synthesis in Human Cells

Clinical Science ◽

10.1042/cs0470617 ◽

1974 ◽

Vol 47 (6) ◽

pp. 617-630

Author(s):

A. Lavoie ◽

E. Tripp ◽

A. V. Hoffbrand

Keyword(s):

Folic Acid ◽

Vitamin B12 ◽

Direct Effect ◽

Vitamin B12 Deficiency ◽

Pernicious Anaemia ◽

Normal Subjects ◽

Normal Cells ◽

Methyl Group ◽

Consistent Effect ◽

B12 Deficiency

1. The uptake of 14C from [methyl-14C]methyItetrahydrofolate was significantly reduced in the phytohaemagglutinin (PHA)-stimulated lymphocytes from nine patients with untreated pernicious anaemia compared with the uptake in seven normal subjects. 2. The uptake of 14C from [14C]methyltetrahydrofolate by the lymphocytes from seven of the patients with pernicious anaemia was consistently increased by addition of vitamin B12in vitro. 3. The proportion of 14C taken up from [14C]methyltetrahydrofolate transferred to non-folate compounds was found to be significantly reduced in the PHA-stimulated lymphocytes from nine patients with untreated pernicious anaemia compared with the proportion transferred in the PHA-stimulated lymphocytes from seven normal subjects. Addition of vitamin B12in vitro consistently increased the transfer in vitamin B12-deficient cells but had no consistent effect in normal cells. 4. Normal and vitamin B12-deficient PHA-stimulated lymphocytes took up [3H]folic acid and after 72 h incubation converted this largely into pteroylpolyglutamate forms. 5. The proportion of labelled lymphocyte folate as pteroylpolyglutamate after incubation with [3H]folic acid was the same in vitamin B12-deficient as in normal lymphocytes and the proportion of pteroylpolyglutamates formed in vitamin B12-deficient lymphocytes was unaffected by addition of vitamin B12in vitro. 6. No radioactivity could be decteted in pteroylpolyglutamates after incubating normal PHA-stimulated lymphocytes with [14C]methyltetrahydrofolate for 72 h, suggesting that pteroylpolyglutamate forms of folate cannot be made directly from methyltetrahydrofolate. 7. These results are consistent with the ‘methyltetrahydrofolate trap’ hypothesis in vitamin B12 deficiency. It is suggested that reduced synthesis of pteroylpolyglutamates reported by others in vitamin B12-deficient cells may be secondary to the failure of removal of the methyl group from methyltetrahydrofolate rather than to a direct effect of vitamin B12 deficiency on the enzyme responsible for pteroylpolyglutamate synthesis. 8. Reduced entry of methyltetrahydrofolate into vitamin B12-deficient cells may be secondary to failure of conversion of this compound into tetrahydrofolate.

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Vitamin B12: A Methyl Group without a Job?

Angewandte Chemie International Edition ◽

10.1002/anie.200502638 ◽

2006 ◽

Vol 45 (6) ◽

pp. 989-993 ◽

Cited By ~ 29

Author(s):

Philip Butler ◽

Marc-Olivier Ebert ◽

Andrzej Lyskowski ◽

Karl Gruber ◽

Christoph Kratky ◽

...

Keyword(s):

Vitamin B12 ◽

Methyl Group

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Biosynthesis of vitamin B12: when is the 12β-methyl group of the vitamin generated by acetate decarboxylation?

Journal of the Chemical Society Chemical Communications ◽

10.1039/c39880001117 ◽

1988 ◽

pp. 1117-1119 ◽

Cited By ~ 8

Author(s):

Francis Blanche ◽

Sheetal Handa ◽

Denis Thibaut ◽

Colin L. Gibson ◽

Finian J. Leeper ◽

...

Keyword(s):

Vitamin B12 ◽

Methyl Group

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Revealing the promoting effect of betaine on vitamin B12 biosynthetic pathway of Pseudomonas denitrificans by using a proteomics analysis

Current Pharmaceutical Biotechnology ◽

10.2174/1389201022666210531120935 ◽

2021 ◽

Vol 22 ◽

Author(s):

Kun-tai Li ◽

Yong Yang ◽

Xin Cheng

Keyword(s):

Vitamin B12 ◽

Biosynthetic Pathway ◽

Aminolevulinic Acid ◽

Fermentation Medium ◽

Promoting Effect ◽

Pseudomonas Denitrificans ◽

Methyl Group ◽

Integral Effect ◽

Comparative Metabolomics ◽

Porphobilinogen Synthase

Background: Our previous comparative metabolomics research revealed that betaine (N,N,N-trimethylglycine, a typically essential methyl-group donor for vitamin B12 biosynthesis) had a powerful promoting effect on the generation of vitamin B12 precursors and intermediates in vitamin B12-producing Pseudomonas denitrificans. However, the integral effect of betaine on the vitamin B12 biosynthetic pathway is still unclear. Objective: Considering the vitamin B12 biosynthetic pathway of P. denitrificans as a whole, this work aimed to reveal the biological function of betaine on the vitamin B12 biosynthetic pathway in P. denitrificans, which would sharpen and expand the understanding of betaine as the methyl-group donor for vitamin B12 biosynthesis. Materials and Methods: By using a proteomics method based on the iTRAQ technique, the present study compared and analyzed the differential expression of proteins involved in vitamin B12 biosynthetic pathway under 10 g/L betaine addition to P. denitrificans fermentation medium. Results: The results showed that betaine could significantly up-regulate the expression of proteins related to the vitamin B12 biosynthetic pathway, which was mainly reflected in the following three aspects: 1) the δ-aminolevulinic acid (ALA) synthase and porphobilinogen synthase that were responsible for the formation of the committed precursors for tetrapyrrole-derived macrocycle in vitamin B12 molecule; 2) the C-methylation-related enzymes (such as precorrin-4 C(11)-methyltransferase, Precorrin-2 C(20)-methyltransferase, Precorrin-8X methylmutase, and Precorrin-6Y C5,15-methyltransferase) and methionine synthase that were crucial to the C-methylation reactions for vitamin B12 biosynthesis; 3) the late-stage key enzymes (Cobaltochelatase, and Cob(I)yrinic acid a,c-diamide adenosyltransferase) that were related to cobalt chelation of vitamin B12 molecule. Conclusions: The present study clearly demonstrated that betaine could significantly promote the expression of the integral enzymes involved in the vitamin B12 biosynthetic pathway of P. denitrificans, thus promoting vitamin B12 biosynthesis.

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VITAMIN B12 FOLACIN AND METHYL GROUP SYNTHESIS

Nutrition Reviews ◽

10.1111/j.1753-4887.1953.tb01364.x ◽

2009 ◽

Vol 11 (7) ◽

pp. 220-221 ◽

Cited By ~ 1

Keyword(s):

Vitamin B12 ◽

Methyl Group

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Vitamin B12 and protein utilization in the chick

The Journal of Agricultural Science ◽

10.1017/s0021859600032858 ◽

1958 ◽

Vol 51 (1) ◽

pp. 90-94

Author(s):

W. O. Brown ◽

R. G. Baskett

Keyword(s):

Vitamin B12 ◽

Direct Effect ◽

Nitrogen Balance ◽

Nitrogen Retention ◽

Vitamin B ◽

Or Efficiency ◽

Protein Utilization ◽

Methyl Group ◽

Experimental Animals

The literature specifically related to the effect of vitamin B12 on methyl group synthesis and its relationship to protein utilization in experimental animals is discussed.The techniques and results of nitrogen balance experiments on control A.P.F.-deficient chicks and vitamin B12-treated chicks are presented.Results show that vitamin B12 administration does not result in any direct effect on nitrogen retention or efficiency of utilization when control and B12-supplemented chicks are pair-fed. This finding is discussed in relation to the response of A.P.F.-deficient chicks to vitamin B12 and the significance of appetite as a factor in the response is suggested.

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