Sources of nitrogen as rate-limiting factors for purine biosynthesis de novo in Ehrlich ascites tumor cells

• Published in: Biochimica et biophysica acta Vol. 177; no. 1; pp. 88 - 93
• Main Authors: Fontenelle, Lydia J., Henderson, J.Frank
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 18.02.1969
• Subjects: Adenine - biosynthesis; Ammonia - metabolism; Animals; Asparagine - metabolism; Aspartic Acid - metabolism; Carbon Isotopes; Carcinoma, Ehrlich Tumor - metabolism; Diphosphates; Drug Synergism; Glutamine; Glycine - metabolism; Hypoxanthines - metabolism; Kinetics; Ligases - metabolism; Methionine Sulfoximine - metabolism; Nitrogen - metabolism; Nucleotides - biosynthesis; Pentosephosphates; Purines - biosynthesis; Transferases - metabolism
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/0304-4165(69)90067-1

Low rates of glutamine synthetase activity furnished glutamine for purine synthesis de novo in Ehrlich ascites tumor cells in vitro and in vivo, but more had to be added exogenously to achieve maximum rates of the latter process. Ammonia could replace glutamine as substrate of phosphoribosylpyrophosphate amidotransferase, but could not do so for phosphoribosylglycineamidine synthetase. Asparagine did not replace glutamine in either reaction. Addition of aspartate also caused an increase in the rate of purine synthesis; the rate of purine synthesis in the presence of added glutamine and aspartate together was greater than that in the presence of either amino acid alone.