Precursors of the pyrimidine moiety of thiamine

• Published in: Biochemical journal 1968-01, Vol.106 (1), p.271-277
• Main Authors: Newell, P C, Tucker, R G
• Format: Article
• Language: English
• Subjects: Amino Acids - metabolism; Carbon Isotopes; Depression, Chemical; Enzyme Repression; Ethionine - pharmacology; Genetics, Microbial; Glycine - metabolism; Methionine - metabolism; Methods; Mutation; Pyrimidines - biosynthesis; Pyrimidines - isolation & purification; Radioisotope Dilution Technique; Salmonella typhimurium - enzymology; Salmonella typhimurium - growth & development; Salmonella typhimurium - metabolism; Thiamine - biosynthesis
• ISSN: 0264-6021; 0306-3283; 1470-8728
• DOI: 10.1042/bj1060271

1. A method was devised for obtaining the pyrimidine moiety of thiamine in a pure form after its excretion into the medium by de-repressed washed-cell suspensions of mutants of Salmonella typhimurium LT2. 2. By using amino acid-requiring mutants, this excretion of pyrimidine moiety was shown to be dependent on the presence of both methionine and glycine. 3. In the presence of either [Me-(14)C]methionine or [G-(14)C]methionine, methionine-requiring mutants did not incorporate radioactivity into the pyrimidine moiety. 4. In contrast, both [1-(14)C]glycine and [2-(14)C]glycine were incorporated into the pyrimidine moiety excreted by glycine-requiring mutants, and this occurred with little or no dilution of specific radioactivity. 5. The possible requirement for methionine as a cofactor and the significance of the incorporation of both carbon atoms of glycine are discussed.