Nitric Oxide Synthase: Difference between revisions

Line 5:

[[Image:NOS_OVERSIGT.JPG|400 px|right]]

The NOS homodimer is composed of two types of domains: an oxygenase domain and a reductase domain. Each subunit is held together by a Zinc ion, which is bound by two cysteines from each oxygenase domain. Binding of the domains is caused by calmodulin (CaM). The reductase domain supplies electrons for the NOS reaction which takes place in the oxygenase domain. The reductase domain contains two redox-active prosthetic groups, flavin adenine dinucleotide (FAD) and Flavin mononucleotide (FMN). Nicotinamide adenine dinucleotide phosphate(NADPH) binds to the domain and passes on an electron to FAD which passes the electron on to FMN. FMN passes the electron on to the Heme in the oxygenase domain on the opposite subunit. The oxygenase domain contains H4B (5,6,7,8-tetrahydrobiopterin)and the already mentioned Heme ion (Fe(III)). These two are also redox active groups~~. H4B is required by NOS in order to produce NO and not H2O2~~. Besides Heme and H4B, the oxygenase domain binds the substrate L-arginine which takes part in the NO synthase reaction (see below).

The NOS homodimer is composed of two types of domains: an oxygenase domain and a reductase domain. Each subunit is held together by a Zinc ion, which is bound by two cysteines from each oxygenase domain. Binding of the domains is caused by calmodulin (CaM). The reductase domain supplies electrons for the NOS reaction which takes place in the oxygenase domain. The reductase domain contains two redox-active prosthetic groups, flavin adenine dinucleotide (FAD) and Flavin mononucleotide (FMN). Nicotinamide adenine dinucleotide phosphate(NADPH) binds to the domain and passes on an electron to FAD which passes the electron on to FMN. FMN passes the electron on to the Heme in the oxygenase domain on the opposite subunit. The oxygenase domain contains H4B (5,6,7,8-tetrahydrobiopterin)and the already mentioned Heme ion (Fe(III)). These two are also redox active groups. Besides Heme and H4B, the oxygenase domain binds the substrate L-arginine which takes part in the NO synthase reaction (see below).

Nitric Oxide Synthase: Difference between revisions

Navigation menu

Page actions

Page actions

Personal tools

Navigation

Search

Tools

Revision as of 11:12, 4 June 2009 view source Sara Toftegaard Petersen (talk \| contribs) 94 edits →Zinc ← Older edit		Revision as of 11:16, 4 June 2009 view source Sara Toftegaard Petersen (talk \| contribs) 94 edits mNo edit summary Newer edit →
Line 5:		Line 5:
	[[Image:NOS_OVERSIGT.JPG\|400 px\|right]]		[[Image:NOS_OVERSIGT.JPG\|400 px\|right]]

	The NOS homodimer is composed of two types of domains: an oxygenase domain and a reductase domain. Each subunit is held together by a Zinc ion, which is bound by two cysteines from each oxygenase domain. Binding of the domains is caused by calmodulin (CaM). The reductase domain supplies electrons for the NOS reaction which takes place in the oxygenase domain. The reductase domain contains two redox-active prosthetic groups, flavin adenine dinucleotide (FAD) and Flavin mononucleotide (FMN). Nicotinamide adenine dinucleotide phosphate(NADPH) binds to the domain and passes on an electron to FAD which passes the electron on to FMN. FMN passes the electron on to the Heme in the oxygenase domain on the opposite subunit. The oxygenase domain contains H<sub>4</sub>B (5,6,7,8-tetrahydrobiopterin)and the already mentioned Heme ion (Fe(III)). These two are also redox active groups~~. H<sub>4</sub>B is required by NOS in order to produce NO and not H<sub>2</sub>O<sub>2</sub>~~. Besides Heme and H<sub>4</sub>B, the oxygenase domain binds the substrate L-arginine which takes part in the NO synthase reaction (see below).		The NOS homodimer is composed of two types of domains: an oxygenase domain and a reductase domain. Each subunit is held together by a Zinc ion, which is bound by two cysteines from each oxygenase domain. Binding of the domains is caused by calmodulin (CaM). The reductase domain supplies electrons for the NOS reaction which takes place in the oxygenase domain. The reductase domain contains two redox-active prosthetic groups, flavin adenine dinucleotide (FAD) and Flavin mononucleotide (FMN). Nicotinamide adenine dinucleotide phosphate(NADPH) binds to the domain and passes on an electron to FAD which passes the electron on to FMN. FMN passes the electron on to the Heme in the oxygenase domain on the opposite subunit. The oxygenase domain contains H<sub>4</sub>B (5,6,7,8-tetrahydrobiopterin)and the already mentioned Heme ion (Fe(III)). These two are also redox active groups. Besides Heme and H<sub>4</sub>B, the oxygenase domain binds the substrate L-arginine which takes part in the NO synthase reaction (see below).