Cloning and Expression of Human eNOS and nNOS Using the Baculovirus-Insect Cell System

To date, the cDNAs and genes encoding three distinct forms of the enzyme nitric oxide synthase (NOS) have been described (reviewed in ref. 1 ). The family of NOS enzymes generate nitric oxide (NO) from arginine, producing citrulline as a co-product and requires the presence of heme, tetrahydrobiopterin (BH₄ ), nicotinamide adenine dinucleotide phosphate (NADPH), calmodulin (CaM), flavin mononucleotide (FMN), and flavine adenine nucleotide (FAD) (2 ). The NO generated by the family of NO synthases has been found to play an important role in many biological processes involved in health and disease including neurotransmission, the mediation of vasodilation, and host defense (2 ).