Substrate inhibition of nitric oxide synthase in pulmonary artery endothelial cells in culture

Yunchao Su, Margaret Couch, Edward R. Block

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)469-475
Number of pages7
JournalNitric Oxide - Biology and Chemistry
Issue number6
StatePublished - Dec 1997
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Clinical Biochemistry
  • Cancer Research


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