The Biosynthesis of 2-Amino-4-hydroxy-6-substituted Pteridines

• Published in: The Journal of biological chemistry Vol. 241; no. 2; pp. 383 - 387
• Main Authors: Krumdieck, C.L., Shaw, Elliott, Baugh, Charles M.
• Format: Journal Article
• Language: English
• Published: American Society for Biochemistry and Molecular Biology 25.01.1966
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)96928-0

The use of uniformly labeled 14 C-cytidine to preferentially label the ribosyl moiety of the purine nucleotides in growing cultures of Corynebacterium species has been shown. This organism was cultivated in a medium supplemented with uniformly labeled 14 C-cytidine and the bacterial growth stopped while the cultures were still in the logarithmic phase. The entire 2-amino-4-hydroxy-6-substituted pteridine pool was isolated, purified, and degraded. The specific radioactivity of carbon atoms 6 and 7 and carbon 9 was determined. Guanylic acid was isolated from the bacterial ribonucleic acid and the specific radioactivity of the ribosyl moiety was determined. The average specific radioactivity of the individual carbon atoms from the ribosyl moiety of guanylic acid was shown to agree very closely with the specific radioactivity of carbon atoms 6,7, and 9 of the pteridines. It is concluded that carbon atoms 6, 7, and 9 of folic acid originate as carbon atoms 2', 1', and 3', respectively, of the ribosyl moiety of guanylic acid. The implications of these findings as regards the biosynthesis of the 2-amino-4-hydroxy-6-substituted pteridines is discussed.