NADPH ferrihemoprotein reductase, also known as NADPH-cytochrome P450 reductase or CPR, is an enzyme that plays a crucial role in cellular metabolism. It is a flavoprotein that belongs to the oxidoreductase enzyme family and is primarily found in the endoplasmic reticulum of mammalian cells.
The main function of NADPH ferrihemoprotein reductase is to transfer electrons from the coenzyme nicotinamide adenine dinucleotide phosphate (NADPH) to various electron acceptors, including cytochrome P450 enzymes. This enzyme is an essential component of the microsomal mixed-function oxidase system, which is responsible for the metabolism of numerous endogenous and exogenous substances such as drugs, steroids, and toxins.
NADPH ferrihemoprotein reductase contains a flavin adenine dinucleotide (FAD) cofactor, which serves as the primary electron acceptor, and a flavin mononucleotide (FMN) prosthetic group. It catalyzes the transfer of electrons from NADPH to the oxidized heme group of cytochrome P450 enzymes, thereby reducing them to their active state. This reduction process is crucial for the enzymatic function of cytochromes and enables them to perform a variety of biochemical reactions.
The activity of NADPH ferrihemoprotein reductase is regulated by various factors, including phosphorylation, protein-protein interactions, and binding of different redox partners. This enzyme's function is vital for maintaining appropriate redox balance and cellular homeostasis, making it an essential enzyme in various physiological processes, including drug metabolism, detoxification, and steroid hormone biosynthesis.
