Developmental changes in the activities of enzymes related to methyl group metabolism in sheep tissues.
The activities of choline oxidase and betaine-homocysteine methyltransferase increased markedly in pre-ruminant lamb liver after birth and subsequently decreased when the lambs reached the ruminant state, while the developmental changes in hepatic 5-methyl-H4folate-homocysteine methyltransferase were negatively correlated with those of betaine-homocysteine methyltransferase. Hepatic phospholipid methyltransferase was elevated almost four-fold by the 10th postnatal day, but declined thereafter. Hepatic glycine methyltransferase in one-day-old lambs increased 55-fold, compared with that of fetuses, and thereafter decreased dramatically with age. Guanidoacetate methyltransferase, glycine methyltransferase and betaine-homocysteine methyltransferase in sheep pancreas increased markedly with age and were many times higher than the hepatic enzymes in adult sheep. Choline oxidase, betaine-homocysteine methyltransferase, cystathionine beta-synthase and glycine methyltransferase in adult sheep liver were much lower than those in rat. These results illustrate the conservative features of methyl group metabolism in postruminant sheep.
D000375:Aging; D000429:Alcohol Oxidoreductases / Q000378:metabolism; D000818:Animals; D050940:Betaine-Homocysteine S-Methyltransferase; D007700:Kinetics; D008099:Liver / Q000201:enzymology / Q000254:growth & development*; D008745:Methylation; D008780:Methyltransferases / Q000378:metabolism*; D012756:Sheep / Q000254:growth & development*
D000429:Alcohol Oxidoreductases; C019888:choline oxidase; D008780:Methyltransferases; D050940:Betaine-Homocysteine S-Methyltransferase