On the substrate specificity of nitric oxide synthase

FEBS Letters

Vane, John R.¹  Hecker, Markus¹  Walsh, Desmond T.¹ 

[1] The William Harvey Research Institute, St. Bartholomew's Hospital Medical College, Charterhouse Square, London EC1M 6BQ, UK

关键词: Nitric oxide synthase;    Calcium;    Structure-activity relationship;    L-Arginine analogue;    Endothelial cell;    Monocyte/macrophage;    EC;    endothelial cell(s);    EGTA;    ethylene glycol-bis(β)-amino ethyl ether) N;    N;    N′-N′-tetraacetic acid;    L-MeArg;    N G-monomethyl-L-arginine;    NO;    nitric oxide;    L-NO2Arg;    N G-nitro-L-arginine;    L-HOArg;    N G-hydroxy-L-arginine;    D-HOArg;    N G-hydroxy-D-arginine;    SOD;    superoxide dismutase;   

DOI  :  10.1016/0014-5793(91)81434-A

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Nitric oxide (NO) synthase (NOS) activity in subcellular fractions from cultured endothelial cells (EC) and lipopolysaccharide-activated J774.2 monocyte/macrophages was investigated by monitoring the NO-mediated increase in intracellular cyclic GMP in LLC-PK₁ pig kidney epithelial cells. The constitutive NOS in EC (NOS_c) was largely membrane-bound, whereas the inducible NOS in J774.2 cells (NOS₁) was equally distributed among cytosol and membrane(s). Both the cytosolic NOS_c in EC and the membrane-bound NOS₁ in J774.2 cells were strictly Ca²⁺-dependent, whereas the membrane-bound NOS_c in EC and the cytosolic NOS₁ in J774.2 cells were not. L-Homoarginine and L-arginine-containing small peptides, such as L-arginyl-L-phenylalanine, replaced L-arginine as a substrate for the NOS_c in EC and the Ca²⁺-independent NOS₁ in J774.2 cells, but not the Ca²⁺-dependent NOS₁. Thus, irrespective of their intracellular localisation, at least three isoforms of NOS exist, which can be differentiated by their substrate specificity and Ca²⁺-dependency.

【 授权许可】

Unknown