Regulation of 5-phosphoribosyl-1-pyrophosphate synthesis in human fibroblasts by the concentration of inorganic phosphate.

摘要: During the growth cycle of normal fibroblasts and deficient in glucose-6-phosphate dehydrogenase activity, concentration 5-phosphoribosyl-1-pyrophosphate Pi, as well activity synthetase, decreased to stable values confluent cultures. A high degree correlation (0.89 0.91 for two 0.69 one dehydrogenase-deficient cell strain, respectively) was shown between intracellular concentrations under varying culture incubation conditions. 5-Phosphoribosyl-1-pyrophosphate were elevated incubated with methylene blue only if Pi levels high. Neither nor 6-aminonicotinamide, singly, affected concentrations. However, when cells pretreated 6-aminonicotinamide then blue, decreased, depleted, its rate generation decreased. Under similar conditions, maintained unaltered levels, slightly increased. The decrease after combined treatment commensurate an accumulation 6-phosphogluconate, which did not take place mutant cells. changes synthesis, whether due stage or various experimental manipulations, always concordant level. regulatory role is consistent known enzymic properties synthetase.