Determination of Km for oxygen of nitric oxide synthase isoforms

Appavoo Rengasamy, Roger A Johns

Research output: Contribution to journalArticle

Abstract

Biosynthesis of nitric oxide (NO) requires L-arginine and molecular oxygen. Although the apparent Km values for L-arginine of NO synthase isoforms have been reported, the apparent Km values for oxygen are unknown. Low oxygen tension has been shown to attenuate NO synthase activity and NO-dependent vascular relaxation. We investigated the effect of different concentrations of oxygen on NO synthase activity of bovine brain, cultured bovine aortic endothelial cells and RAW 264.7 macrophages. The apparent Km values for oxygen were 23.2 ± 2.8, 7.7 ± 1.6 and 6.3 ± 0.9 μM for the brain, endothelial and macrophage NO synthases, respectively. This suggests that pathophysiological conditions involving a decrease in tissue oxygen concentration may attenuate NO production.

Original languageEnglish (US)
Pages (from-to)30-33
Number of pages4
JournalJournal of Pharmacology and Experimental Therapeutics
Volume276
Issue number1
StatePublished - Jan 1996
Externally publishedYes

Fingerprint

Nitric Oxide Synthase
Protein Isoforms
Oxygen
Nitric Oxide
Arginine
Macrophages
Nitric Oxide Synthase Type III
Brain
Blood Vessels
Endothelial Cells

ASJC Scopus subject areas

  • Pharmacology

Cite this

Determination of Km for oxygen of nitric oxide synthase isoforms. / Rengasamy, Appavoo; Johns, Roger A.

In: Journal of Pharmacology and Experimental Therapeutics, Vol. 276, No. 1, 01.1996, p. 30-33.

Research output: Contribution to journalArticle

@article{b25e4827e1c34bcca6a45b3cb807fd27,
title = "Determination of Km for oxygen of nitric oxide synthase isoforms",
abstract = "Biosynthesis of nitric oxide (NO) requires L-arginine and molecular oxygen. Although the apparent Km values for L-arginine of NO synthase isoforms have been reported, the apparent Km values for oxygen are unknown. Low oxygen tension has been shown to attenuate NO synthase activity and NO-dependent vascular relaxation. We investigated the effect of different concentrations of oxygen on NO synthase activity of bovine brain, cultured bovine aortic endothelial cells and RAW 264.7 macrophages. The apparent Km values for oxygen were 23.2 ± 2.8, 7.7 ± 1.6 and 6.3 ± 0.9 μM for the brain, endothelial and macrophage NO synthases, respectively. This suggests that pathophysiological conditions involving a decrease in tissue oxygen concentration may attenuate NO production.",
author = "Appavoo Rengasamy and Johns, {Roger A}",
year = "1996",
month = "1",
language = "English (US)",
volume = "276",
pages = "30--33",
journal = "Journal of Pharmacology and Experimental Therapeutics",
issn = "0022-3565",
publisher = "American Society for Pharmacology and Experimental Therapeutics",
number = "1",

}

TY - JOUR

T1 - Determination of Km for oxygen of nitric oxide synthase isoforms

AU - Rengasamy, Appavoo

AU - Johns, Roger A

PY - 1996/1

Y1 - 1996/1

N2 - Biosynthesis of nitric oxide (NO) requires L-arginine and molecular oxygen. Although the apparent Km values for L-arginine of NO synthase isoforms have been reported, the apparent Km values for oxygen are unknown. Low oxygen tension has been shown to attenuate NO synthase activity and NO-dependent vascular relaxation. We investigated the effect of different concentrations of oxygen on NO synthase activity of bovine brain, cultured bovine aortic endothelial cells and RAW 264.7 macrophages. The apparent Km values for oxygen were 23.2 ± 2.8, 7.7 ± 1.6 and 6.3 ± 0.9 μM for the brain, endothelial and macrophage NO synthases, respectively. This suggests that pathophysiological conditions involving a decrease in tissue oxygen concentration may attenuate NO production.

AB - Biosynthesis of nitric oxide (NO) requires L-arginine and molecular oxygen. Although the apparent Km values for L-arginine of NO synthase isoforms have been reported, the apparent Km values for oxygen are unknown. Low oxygen tension has been shown to attenuate NO synthase activity and NO-dependent vascular relaxation. We investigated the effect of different concentrations of oxygen on NO synthase activity of bovine brain, cultured bovine aortic endothelial cells and RAW 264.7 macrophages. The apparent Km values for oxygen were 23.2 ± 2.8, 7.7 ± 1.6 and 6.3 ± 0.9 μM for the brain, endothelial and macrophage NO synthases, respectively. This suggests that pathophysiological conditions involving a decrease in tissue oxygen concentration may attenuate NO production.

UR - http://www.scopus.com/inward/record.url?scp=0029664647&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0029664647&partnerID=8YFLogxK

M3 - Article

C2 - 8558447

AN - SCOPUS:0029664647

VL - 276

SP - 30

EP - 33

JO - Journal of Pharmacology and Experimental Therapeutics

JF - Journal of Pharmacology and Experimental Therapeutics

SN - 0022-3565

IS - 1

ER -