Carbonic anhydrase (CA) is the zinc metalloenzyme that catalyses the reversible reactions of CO(2) with water. CA plays a crucial role in systemic acid-base regulation in fish by providing acid-base equivalents for exchange with the environment. Unlike air-breathing vertebrates, which frequently utilize alterations of breathing (respiratory compensation) to regulate acid-base status, acid-base ...

Carbonic anhydrase (CA; EC 4.2.1.1) is a zinc metalloenzyme catalysing the reversible hydration of CO2 to produce H+ and HCO3−. Its activity is virtually ubiquitous in nature. The fundamental role of this biochemical reaction in diverse biological systems has driven the evolution of several distinct and unrelated families of CAs. Five CA families, referred as ┙-, ┚-, ┛-CA, ├, and ζ-CAs have bee...

On the basis of polyacrylamide gradient gel electrophoresis of leaf extracts from 24 species of higher plants, two main forms of carbonic anhydrase (EC 4.2.1.1) were recognized; the "dicotyledon" type and the "monocotyledon" type. More than one band of enzyme was found on gels from most species, suggesting the possibility of carbonic anhydrase isoenzymes in higher plants.

We studied the relationship between alpha- and beta-adrenergic agonists and the activity of carbonic anhydrase I and II in erythrocyte, clinical and vessel studies. Kinetic studies were performed. Adrenergic agonists increased erythrocyte carbonic anhydrase as follows: adrenaline by 75%, noradrenaline by 68%, isoprenaline by 55%, and orciprenaline by 62%. The kinetic data indicated a non-compet...

Ion mobility experiments coupled with electrospray ionization (ESI) were conducted to evaluate the folding states of bovine carbonic anhydrase 2 (CA2) under three different pH conditions. Collision cross-section (CCS) of the CA2 ions generated by ESI revealed the presence of six discrete conformers in the gas phase under the conditions employed in this study. The CCS of the most extended confor...

'13Cd NMR of the "3Cd(II)-substituted zinc metalloenzymes, human and bovine erythrocyte carbonic anhydrases, is reported. The high activity isozymes, human erythrocyte carbonic anhydrase, isozyme C (HCAC) and bovine erythrocyte carbonic anhydrase, isozyme B (BCAB), are characterized by relatively narrow '13Cd resonances around 220 ppm to lowfield of Cd(C104)Z. These resonances are relatively in...

By BERT L. VALLEE, M.D., HERBERT D. LEWIS, M.D., MARK D. ALTSCHULE, M.D., AND JOHN G. GIBSON, II, M.D. I T HAS been shown that zinc is a component of the carbonic anhydrase molecule.” 2 This enzyme has been demonstrated to catalyze the reaction H,O + CO, ± H,CO, in vitro; its molecular weight is approximately half that of hemoglobin,’ and some of its other physico-chemical properties are establ...

Davenport and Fisher (1938) and Davenport (1939, 1940) have shown that there is a high concentration of carbonic anhydrase in the parietal cells and a lower concentration in the cells of the surface epithelium of the gastric mucosa of rats, cats and dogs. They expressed the belief that the enzyme is part of the mechanism which secretes hydrochloric acid. Davenport argued that carbon dioxide is ...

Proteins with reactive sulfhydryls are central to many important metabolic reactions and also contribute to a variety of signal transduction systems. In this report, we examine the mechanisms of oxidative damage to the two reactive sulfhydryls of carbonic anhydrase III. Hydrogen peroxide (H2O2), peroxy radicals, or hypochlorous acid (HOCl) produced irreversibly oxidized forms, primarily cystein...