Regulation of purine de novo synthesis in cultured human fibroblasts: The role of P-Ribose-PP

Gordon R.B., Thompson L., Johnson L.A. and Emmerson B.T. (1979) Regulation of purine de novo synthesis in cultured human fibroblasts: The role of P-Ribose-PP. BBA Section Nucleic Acids And Protein Synthesis, 562 1: 162-176. doi:10.1016/0005-2787(79)90135-7


Author Gordon R.B.
Thompson L.
Johnson L.A.
Emmerson B.T.
Title Regulation of purine de novo synthesis in cultured human fibroblasts: The role of P-Ribose-PP
Journal name BBA Section Nucleic Acids And Protein Synthesis
ISSN 0005-2787
Publication date 1979-03-28
Sub-type Article (original research)
DOI 10.1016/0005-2787(79)90135-7
Open Access Status Not yet assessed
Volume 562
Issue 1
Start page 162
End page 176
Total pages 15
Subject 2700 Medicine
Abstract Procedures for assaying the rate of purine de novo synthesis in cultured fibroblast cells have been compared. These were (i) the incorporation of [14C]glycine or [14C]formate in α-N-formylglycinamide ribonucleotide (an intermediate in the purine synthetic pathway) and (ii) the incorporation of [14C]formate into newly synthesised cellular purines and purines excreted by the cell into the medium. Fibroblast cells, derived from patients with a deficiency of hypoxanthine phosphoribosyltransferase (HPRT-) (EC 2.4.2.8) and increased rates of purine de novo synthesis, were compared with fibroblasts from healthy subjects (HPRT+). Fetal calf serum, which was used to supplement the assay and cell growth medium, was found to contain sufficient quantities of the purine base hypoxanthine to inhibit purine de novo synthesis in HPRT+ cells. This inhibition was the basis of differentiation between HPRT- and HPRT+ cells. In the absence of added purine base, both cell types had similar capacities for purine de novo synthesis. This result contrasts with the increased rates of purine de novo synthesis reported for a number of human HPRT- cells in culture but confirms recent studies made on human HPRT- lymphoblast cells. The intracellular concentration and utilisation of 5-phosphoribosyl-1-pyrophosphate (P-Rib-PP), a substrate and potential controlling factor for purine de novo synthesis, were determined in HPRT- and HPRT+ cells. The rate of utilisation of P-Rib-PP in the salvage of free purine bases was far greater than that in purine de novo synthesis. Although HPRT- cells had a 3-fold increase in P-Rib-PP content, the rate of P-Rib-PP generation was similar to HPRT+ cells. Thus, in fibroblasts, the concentration of P-Rib-PP appears to be critical in the control of de novo purine synthesis and its preferential utilisation in the HPRT reaction limits its availability for purine de novo synthesis. In vivo, HPRT+ cells, in contrast to HPRT- cells, may be operating purine de novo synthesis at a reduced rate because of their ability to reutilise hypoxanthine.
Keyword (Human fibroblast)
Hypoxanthine phosphoribosyltransferase
P-Ribose-PP
Purine synthesis regulation
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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