The nitrogen-sparing effect of methionine sulphoxide and some other sulphur-containing amino acids.
The nitrogen-sparing effect of methionine, methionine sulphoxide, homocystine, cystine and choline was studied in rats by determining dialy N excretions during 5 d after changing from a high-protein diet to a protein-free diet, L-glutamic acid was used as a negative control. 2. L-, D- and DL-methionine were equally active in sparing N. L-methionine sulphoxide, DL-homocystine and L-cystine were as active as L-methionine. D-methionine sulphoxide was slightly less active than L-methionine sulphoxide. Choline hydrogen tartrate was not different from the negative control. 3. It is concluded that in short-term experiments cystine is the key substance in the N-sparing effect.
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D002794:Choline / Q000378:metabolism; D003553:Cystine / Q000378:metabolism; D004044:Dietary Proteins / Q000378:metabolism; D006711:Homocystine / Q000378:metabolism; D008297:Male; D008715:Methionine / Q000031:analogs & derivatives* / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism* / Q000652:urine; D051381:Rats
D000596:Amino Acids; D004044:Dietary Proteins; D006711:Homocystine; D003553:Cystine; D008715:Methionine; D009584:Nitrogen; D002794:Choline; C013111:methionine sulfoxide