Faculty Collaboration Database

Oxygen dependency of monoamine oxidase activity in the intact lung. Am J Physiol Lung Cell Mol Physiol 2001 Oct;281(4):L969-81

Date

09/15/2001

Pubmed ID

11557601

DOI

10.1152/ajplung.2001.281.4.L969

Scopus ID

2-s2.0-0034796526 (requires institutional sign-in at Scopus site)   10 Citations

Abstract

Hydrogen peroxide generated by monoamine oxidase (MAO)-mediated deamination of biogenic amines has been implicated in cell signaling and oxidative injury. Because the pulmonary endothelium is a site of metabolism of monoamines present in the venous return, this brings into question a role for MAO in hyperoxic lung injury. The objective of this study was to evaluate the O(2) dependency of the MAO reaction in the lung. To this end, we measured the pulmonary venous effluent concentrations of the MAO substrate [(14)C]phenylethylamine and its metabolite [(14)C]phenylacetic acid after the bolus injection of either phenylethylamine or phenylacetic acid into the pulmonary artery of perfused rabbit lungs over a range of PO(2) values from 16 to 518 Torr. The apparent Michaelis constant for O(2) was approximately 18 microM, which is more than an order of magnitude less that measured for purified MAO. The results suggest a minimal influence of high O(2) on MAO activity in the normal lung and demonstrate the importance of measuring reaction kinetics in the intact organ.

Author List

Audi SH, Dawson CA, Ahlf SB, Roerig DL

Author

Said Audi PhD Professor in the Biomedical Engineering department at Marquette University

MESH terms used to index this publication - Major topics in bold

Animals
Carbon Radioisotopes
Carcinogens
Enzyme Activation
In Vitro Techniques
Lung
Models, Biological
Monoamine Oxidase
Monoamine Oxidase Inhibitors
Oxygen
Pargyline
Phenethylamines
Phenylacetates
Pulmonary Artery
Rabbits
Semicarbazides