High impact information on Qprt

• Hepatic quinolinate phosphoribosyltransferase (EC 2.4.2.19) activity increased with dietary clofibrate and returned to the control level 1 week after removing clofibrate from the diet [1].
• High dietary levels of leucine did not affect the activity of hepatic tryptophan pyrrolase or quinolinate phosphoribosyltransferase, which are key enzymes in the tryptophan leads to NAD pathway [2].
• Of the other treatments, only LCFA influenced mRNA expression of ACMSDase (-3.62-fold reduction) and quinolinate phosphoribosyltransferase (QAPRTase, EC 2.4.2.19) (-2.42-fold) without any change in urinary NMN excretion [3].
• 5. The results indicate that a decrease in NAD biosynthesis from tryptophan caused by metabolites of leucine in the isolated rat liver cells was neither due to insufficient supply of quinolinate nor to direct inhibitory effect on quinolinate phosphoribosyltransferase [4].
• 4. Leucine and its metabolites added in vitro at 1 mM level did not inhibit quinolinate phosphoribosyltransferase activity in rat liver homogenate [4].

Associations of Qprt with chemical compounds

• 4. Quinolinate phosphoribosyltransferase (EC 2.4.2.a) activity in liver was inversely related to dietary protein level, and nicotinic acid in the diet had no effect on its activity [5].
• 3. Less quinolinate accumulated during incubation with metabolites of leucine, however, the amount was still sufficient to saturate quinolinate phosphoribosyltransferase (EC 2.4.2.19) [4].
• In the test group, the amounts of quinolinic acid, niacin, NAD and N1-methylnicotinamide, and the activities of quinolinate phosphoribosyltransferase, nicotinamide mononucleotide adenylyltransferase, nicotinamide methyltransferase and NAD synthetase expressed in terms of g liver were significantly decreased compared to the control group [6].

Analytical, diagnostic and therapeutic context of Qprt

• The reaction mixture of QPRT assay was stopped by immersing the tube into a boiling water bath, the resulting supernatant was filtered, and the filtrate was directly injected into a HPLC system [7].
• Reversed-phase high-performance liquid chromatography of nicotinic acid mononucleotide for measurement of quinolinate phosphoribosyltransferase [7].

References