title: The effect of increasing methionine supply on the methionine conversion to cyst(e)ine in sheep.
abstract: The conversion of methionine to cyst(e)ine was determined in sheep infused with different amounts of methionine (0-5 g/d) into the duodenum by assaying the incorporation of 35S from intravenously-infused L-[35S]methionine into cyst(e)ine in wool, plasma albumin and the free plasma pool. The percentage of cystine-S in the plasma originating from methionine increased linearly from 4.5 to 18 with increasing supplemental methionine supply. The percentage of cysteine-S in albumin increased from 15 to 50; methionine supply increased to 3 g/d but then remained constant, indicating that the transsulphuration pathway of the liver was exceeded. The percentage of wool cysteine-S originating from methionine was high (approximately 70) at all methionine supplementation rates.
mesh_terms: D000818:Animals; D003545:Cysteine / Q000097:blood / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D008715:Methionine / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D012044:Regression Analysis; D012756:Sheep / Q000378:metabolism*; D012867:Skin / Q000378:metabolism
chemical_list: D008715:Methionine; D003545:Cysteine