QPRT Human
Description
Product Specs
Product Science Overview
Human QPRT is a member of the type II phosphoribosyltransferase family. It catalyzes the formation of nicotinic acid mononucleotide from quinolinic acid, involving a phosphoribosyl transfer reaction followed by decarboxylation . The enzyme adopts a hexameric arrangement, placing the active sites in close proximity to each other . The active site of QPRT consists of three arginine residues (R102, R138, and R161) and two lysine residues (K139 and K171), which are crucial for substrate binding and enzymatic activity .
The human QPRT gene is located on chromosome 16 at the cytogenetic location 16p11.2 . Using partial amino acid sequences obtained from purified porcine kidney QPRTase, researchers isolated a human isolog from a brain cDNA library . The human QPRT encodes a predicted 297-amino acid protein with a molecular mass of 30 kDa . The protein has an N-terminal cleavable signal sequence and shares 30 to 40% identity with bacterial QPRTases . To confirm the functionality of the cloned human QPRTase, it was expressed in Escherichia coli, and enzymatic activity was detected, rescuing a QPRTase-defective E. coli strain .
Quinolinic acid is a potent endogenous excitotoxin to neuronal cells, causing neuronal damage through sustained activation of glutamate NMDA receptors . The reduction of quinolinic acid levels by QPRT is crucial in preventing excitotoxicity and potential neuronal damage. Therefore, QPRT has been implicated in various neurological conditions, and understanding its structure and function is vital for developing therapeutic strategies .
Recombinant human QPRT is produced using recombinant DNA technology, where the human QPRT gene is cloned and expressed in a suitable host system, such as Escherichia coli . This recombinant enzyme is used in research to study its structure, function, and potential therapeutic applications. The recombinant form retains the enzymatic activity and structural characteristics of the native enzyme, making it a valuable tool for biochemical and pharmacological studies .
