Biomaterial Database

A purine auxotroph deficient in phosphoribosylpyrophosphate amidotransferase and phosphoribosylpyrophosphate aminotransferase activities with normal activity of ribose-5-phosphate aminotransferase. 1976

E W Holmes, and G L King, and A Leyva, and S C Singer

Three enzyme reactions have been reported to catalyze the synthesis of phosphoribosylamine in eukaryotic cells. These activities are glutamine phosphoribosylpyrophosphate (P-Rib-P-P) amidotransferase [amidophosphoribosyl-transferase; 5-phosphoribosylamine: pyrophosphate phosphoribosyltransferase (glutamate-amidating) EC 2.4.2.14], ammonia P-Rib-P-P aminotransferase, and ammonia ribose-5-phosphate aminotransferase. A purine auxotroph derived from a cell line of Chinese hamster fibroblasts was shown to be deficient in catalytic activities of glutamine P-Rib-P-P amidotransferase and ammonia P-Rib-P-P aminotransferase. Extracts from this cell line had normal ammonia ribose-5-phosphate aminotransferase activity. The defect in purine biosynthesis in the mutant cell line was localized to the synthesis of phosphoribosylamine. These results indicate that glutamine P-Rib-P-P amidotransferase or ammonia P-Rib-P-P aminotransferase or both are important for phosphoribosylamine synthesis, but that ammonia ribose-5-phosphate aminotransferase activity probably does not play a significant role in this eukaryotic cell line. The simultaneous disappearance of both P-Rib-P-P-dependent activities suggests these two enzyme activities are closely related structurally or genetically.

UI	MeSH Term	Description	Entries
D008025	Ligases	A class of enzymes that catalyze the formation of a bond between two substrate molecules, coupled with the hydrolysis of a pyrophosphate bond in ATP or a similar energy donor. (Dorland, 28th ed) EC 6.	Ligase,Synthetases,Synthetase
D010428	Pentosephosphates
D010430	Pentosyltransferases	Enzymes of the transferase class that catalyze the transfer of a pentose group from one compound to another.
D010754	Phosphoribosyl Pyrophosphate	The key substance in the biosynthesis of histidine, tryptophan, and purine and pyrimidine nucleotides.	Pyrophosphate, Phosphoribosyl
D011687	Purines	A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D000582	Amidophosphoribosyltransferase	An enzyme, involved in the early steps of purine nucleotide biosynthesis, that catalyzes the formation of 5-phosphoribosylamine from glutamine and phosphoribosylpyrophosphate. EC 2.4.2.14.	Glutamine Phosphoribosyl Pyrophosphate Amidotransferase,Phosphoribosyl Pyrophosphate Amidotransferase,Glutamine-Amidophosphoribosyltransferase,Phosphoribosyldiphosphate 5-Amidotransferase,5-Amidotransferase, Phosphoribosyldiphosphate,Amidotransferase, Phosphoribosyl Pyrophosphate,Glutamine Amidophosphoribosyltransferase,Phosphoribosyldiphosphate 5 Amidotransferase,Pyrophosphate Amidotransferase, Phosphoribosyl
D000637	Transaminases	A subclass of enzymes of the transferase class that catalyze the transfer of an amino group from a donor (generally an amino acid) to an acceptor (generally a 2-keto acid). Most of these enzymes are pyridoxyl phosphate proteins. (Dorland, 28th ed) EC 2.6.1.	Aminotransferase,Aminotransferases,Transaminase
D000641	Ammonia	A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as AMMONIUM HYDROXIDE.
D012267	Ribosemonophosphates	Ribose substituted in the 1-, 3-, or 5-position by a phosphoric acid moiety.