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The effects of folate, choline and betaine on transmethylation in a methionine restricted piglet
Author(s) -
Robinson Jason L,
McBreairty Laura E.,
Brunton Janet A.,
Bertolo Robert F.
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1077.24
Subject(s) - transmethylation , methionine , choline , betaine , homocysteine , methylation , creatine , chemistry , methyltransferase , phosphatidylcholine , biochemistry , dna methylation , medicine , endocrinology , amino acid , biology , dna , phospholipid , gene , gene expression , membrane
Methionine is an essential amino acid that is incorporated into protein and is also the primary methyl donor for transmethylation reactions via S‐adenosylmethionine (SAM), SAM is demethylated to S‐adenosylhomocysteine (SAH) with the majority of methyl groups either being transferred to DNA or used for synthesis of creatine (CR) and phosphatidylcholine (PC). SAH is converted to homocysteine (HCY) which can be oxidized or remethylated back to methionine by the methyl donors folate and choline (via betaine). 4–8 d old neonatal piglets were fed a diet devoid (n=8) or replete (n=7) of these methyl donors. After 5 d, dietary methionine was reduced to 80% of requirement. On day 8, animals received a constant infusion of [ 3 H]methyl‐methionine for 6 h to measure flux to PC, CR, and DNA. Methyl deficient pigs had a lower SAM/SAH ratio and higher plasma HCY (p<0.05). Methylation to CR, but not PC and DNA, was lower in methyl deficiency, suggesting this methylation reaction is most sensitive to methyl supply. Moreover, methylation of phosphatidylethanolamine to PC tended to be higher with methyl deficiency suggesting this pathway is upregulated when choline is deficient. Severe restriction of remethylation in piglets reduces methionine availability for creatine synthesis. (CIHR funded). Grant Funding Source: CIHR