Purification of a distinctive form of endotoxin-induced nitric oxide synthase from rat liver

Evans, T., Carpenter, A. and Cohen, J. (1992) Purification of a distinctive form of endotoxin-induced nitric oxide synthase from rat liver. Proceedings of the National Academy of Sciences of the United States of America, 89(12), pp. 5361-5365. (PMID:137691) (PMCID:PMC49291)

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Abstract

An endotoxin-induced form of nitric oxide synthase (EC 1.14.23) was purified to homogeneity from rat liver by sequential anion-exchange chromatography and affinity chromatography using 2',5'-ADP-Sepharose. The enzyme has a subunit molecular mass of 135 kDa as determined by SDS/PAGE, a maximum specific activity of 462 nmol of citrulline formed from arginine per min per mg, and a Km for arginine of 11 microM. The enzyme was strongly stimulated by the addition of calmodulin with an EC50 of 2 nM, but removal of free calcium from the assay medium only reduced activity by 15%. Calmodulin inhibitors significantly reduced the enzyme activity. Tetrahydrobiopterin, FAD, and FMN were all required for full enzyme activity. This form of endotoxin-induced nitric oxide synthase from liver differs from the inducible enzyme found in macrophages and is unusual in that it is stimulated by calmodulin with little dependence on the calcium ion concentration.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Evans, Professor Tom
Authors: Evans, T., Carpenter, A., and Cohen, J.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
Journal Name:Proceedings of the National Academy of Sciences of the United States of America
Publisher:National Academy of Sciences
ISSN:0027-8424
ISSN (Online):1091-6490

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