TY - JOUR
T1 - Substrate inhibition of nitric oxide synthase in pulmonary artery endothelial cells in culture
AU - Su, Yunchao
AU - Couch, Margaret
AU - Block, Edward R.
N1 - Funding Information:
1This work was supported by the Medical Research Service of the Department of Veterans Affairs and by NIH Grant HL52136.
PY - 1997/12
Y1 - 1997/12
N2 - The effects of arginine on nitric oxide synthase (NOS) activity and NO production were studied in pulmonary artery endothelial cells (PAEC). Incubation of PAEC with 0-100 μM arginine increased NO production, detected as nitrite in the culture medium, in a dose- dependent manner. In contrast, incubation with concentrations of arginine in excess of 100 μM resulted in a reversible dose-dependent inhibition of NO production, even though intracellular arginine content increased in these cells. The NOS enzyme kinetics were studied in a total membrane preparation and in purified NOS protein and revealed that the K(m) of arginine as a substrate for NOS is 3-5 μM, the V(max) occurred at 100 μM arginine, and substrate inhibition occurred at >100 μM arginine. Oxyhemoglobin, carboxy-PTIO, catalase, SOD, citrulline, hydroxyarginine, and D-arginine did not change NOS kinetics. Those results indicate that substrate inhibition of eNOS exists in porcine PAEC in vitro.
AB - The effects of arginine on nitric oxide synthase (NOS) activity and NO production were studied in pulmonary artery endothelial cells (PAEC). Incubation of PAEC with 0-100 μM arginine increased NO production, detected as nitrite in the culture medium, in a dose- dependent manner. In contrast, incubation with concentrations of arginine in excess of 100 μM resulted in a reversible dose-dependent inhibition of NO production, even though intracellular arginine content increased in these cells. The NOS enzyme kinetics were studied in a total membrane preparation and in purified NOS protein and revealed that the K(m) of arginine as a substrate for NOS is 3-5 μM, the V(max) occurred at 100 μM arginine, and substrate inhibition occurred at >100 μM arginine. Oxyhemoglobin, carboxy-PTIO, catalase, SOD, citrulline, hydroxyarginine, and D-arginine did not change NOS kinetics. Those results indicate that substrate inhibition of eNOS exists in porcine PAEC in vitro.
UR - http://www.scopus.com/inward/record.url?scp=0031417917&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031417917&partnerID=8YFLogxK
U2 - 10.1006/niox.1997.0151
DO - 10.1006/niox.1997.0151
M3 - Article
C2 - 9466952
AN - SCOPUS:0031417917
SN - 1089-8603
VL - 1
SP - 469
EP - 475
JO - Nitric Oxide - Biology and Chemistry
JF - Nitric Oxide - Biology and Chemistry
IS - 6
ER -