POR Human
Greater than 95.0% as determined by SDS-PAGE.
Description
Product Specs
Product Science Overview
P450 oxidoreductase (POR), also known as NADPH:ferrihemoprotein oxidoreductase, is a crucial enzyme in the electron transfer chain. It facilitates the transfer of electrons from NADPH to cytochrome P450 enzymes and other heme proteins, including heme oxygenase, within the endoplasmic reticulum of eukaryotic cells .
The human POR gene is located on chromosome 7 (7q11.23) and consists of 16 exons. The exons 2-16 encode a 677-amino acid protein . The POR protein is a membrane-bound enzyme composed of four structural domains: the FMN-binding domain, the connecting domain, the FAD-binding domain, and the NADPH-binding domain. The FMN-binding domain resembles the structure of FMN-containing protein flavodoxin, while the FAD-binding and NADPH-binding domains are similar to those of flavoprotein ferredoxin-NADP+ reductase (FNR) .
POR plays a vital role in the electron transfer process necessary for the catalytic activity of cytochrome P450 enzymes. The general scheme of electron flow in the POR/P450 system is: NADPH → FAD → FMN → P450 → O2 . This electron transfer is essential for various biochemical processes, including the biosynthesis of cholesterol, sterols, and steroid hormones, as well as the metabolism of more than 80% of clinically used drugs .
Recombinant human POR can be expressed in Escherichia coli and purified for various studies. The expression and purification protocols involve genotyping human POR for common polymorphisms, assessing the effect of amino-acid sequence variants on the activity of various cytochromes P450, and evaluating the enzyme’s activity .
Human POR deficiency can lead to a complex disorder of steroidogenesis and, in severe cases, a skeletal disorder known as Antley-Bixler syndrome . The POR gene is highly polymorphic, with numerous single-nucleotide polymorphisms (SNPs) identified in different ethnic groups. These polymorphisms can affect drug metabolism and steroid biosynthesis, contributing to pharmacogenetic variation in drug response and variations in steroid synthesis .
