Abstract
Quinolinic acid phosphoribosyltransferase (EC 2.4.2.19) was purified 3600-fold from rat liver and 280-fold from rat brain. Kinetic analyses ( K m = 12 μM for the substrate quinolinic acid and K m 23 μM for the cosubstrate phosphoribosylpyrophosphate), physicochemical properties of the purified enzymes, inhibition by phthalic acid ( K i = 1.4 μM) and molecular weight determination ( M r 160 000 for the holoenzyme, consisting of five identical 32 kDa subunits) indicated the structural identity of quinolinic acid phosphoribosyltransferase from the two rat tissues. This was further confirmed immunologically, using antibodies raised against purified rat liver quinolinic acid phosphoribosyltransferase. Rat quinolinic acid phosphoribosyltransferase differs in several aspects from quinolinic acid phosphoribosyltransferase isolated from other organisms. The purified enzyme will prove a useful tool in the examination of a possible role of quinolinic acid in cellular function and/or dysfunction.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
