Nitric Oxide Synthase: Difference between revisions
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<StructureSection load='2g6h' size='350' side='right' caption='Neuronal nitric oxide synthase dimer complex with cofactor tetrahydrobiopterin, acetate and Zn+2 (grey), (PDB entry [[2g6h]])' scene=''> | <StructureSection load='2g6h' size='350' side='right' caption='Neuronal nitric oxide synthase dimer complex with cofactor tetrahydrobiopterin, acetate and Zn+2 (grey), (PDB entry [[2g6h]])' scene=''> | ||
'''Nitric Oxide Synthase''' (NOS) is an enzyme catalysing the formation of L-citrulline and [http://en.wikipedia.org/wiki/Nitric_Oxide/ nitric oxide] (NO) from L-arginine. NOS is a homodimeric protein with 125- to 160-kDa per monomer. In mammals, NOS appears as 3 isozymes: neuronal NOS (nNOS) (for details see [[Nos1]]), cytokine-inducible NOS (iNOS) and endothelial NOS (eNOS). The N-terminal domain of NOS is an oxygenase domain (OD). NOS cofactors are: NADPH, FAD, FMN, heme and O2. See also [[Nos1]]. | '''Nitric Oxide Synthase''' (NOS) or '''Nitric Oxide Synthase oxygenase''' is an enzyme catalysing the formation of L-citrulline and [http://en.wikipedia.org/wiki/Nitric_Oxide/ nitric oxide] (NO) from L-arginine. NOS is a homodimeric protein with 125- to 160-kDa per monomer. In mammals, NOS appears as 3 isozymes: neuronal NOS (nNOS) (for details see [[Nos1]]), cytokine-inducible NOS (iNOS) and endothelial NOS (eNOS). The N-terminal domain of NOS is an '''oxygenase''' domain (OD). NOS cofactors are: NADPH, FAD, FMN, heme and O2. See also [[Nos1]]. | ||
=Introduction= | =Introduction= | ||
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The NO production takes plase in the oxygenase domain, whereas the reductase domain provides the electrons necessary to drive the reaction in the oxygenase domain. | The NO production takes plase in the oxygenase domain, whereas the reductase domain provides the electrons necessary to drive the reaction in the oxygenase domain. | ||
The reaction is: | The reaction is: | ||
[[image:Makroprojekt-chemdraw-1-.gif|left|thumb|400px]] | [[image:Makroprojekt-chemdraw-1-.gif|frame|left|thumb|400px]] | ||
{{Clear}} | {{Clear}} | ||
The reaction occurs in two steps. In the first step L-arginine is turned in to N-hydroxy-arginine. In the second step L-citrulline and NO are formed. The reaction utilizes 2O<sub>2</sub> and 3 electrons from 3/2 NADPH.<ref>PMID:17014963</ref> | The reaction occurs in two steps. In the first step L-arginine is turned in to N-hydroxy-arginine. In the second step L-citrulline and NO are formed. The reaction utilizes 2O<sub>2</sub> and 3 electrons from 3/2 NADPH.<ref>PMID:17014963</ref> | ||