The enzyme carbonic anhydrase appears to be a central molecular component in the suite of physiological and biochemical adaptations to low salinity found in euryhaline crustaceans. It is present in high activities in the organs responsible for osmotic and ionic regulation, the gills, and more specifically, the individual gills that are specialized for active ion uptake from dilute sea water. Wi...

We report the changes in the concentrations and (18)O contents of extracellular CO(2) and HCO(3) (-) in suspensions of Synechococcus sp. (UTEX 2380) using membrane inlet mass spectrometry. This marine cyanobacterium is known to have an active uptake mechanism for inorganic carbon. Measuring (18)O exchange between CO(2) and water, we have found the intracellular carbonic anhydrase activity to be...

Red cell lysis in isotonic solutions containing NH4Cl, NH4HCO3, and a carbonic anhydrase enzyme inhibitor (acetazolamide) is a function of erythrocyte enzyme activity and permeability of cells to the inhibitor. Erythrocyte carbonic anhydrase activity is at least fivefold greater and acetazolamide permeability about tenfold less for adults than for newborns. In this setting, greater than 99.9% o...

The effect of anthraquinone derivatives (anthraquinone, sodium anthraquinone T-sulfonate, anthrarufin and enthrone) and other compounds (a-naphthoquinone, lecithin and tannic acid) on progestational proliferation produced by progesterone in the rabbit uterus was investigated by measurements of endometrial carbonic anhydrase activity. In immature rabbits primed with estrogen, the subcutaneous ad...

BACKGROUND Inhaled frusemide but not bumetanide, another loop diuretic, reduces bronchial responsiveness to sodium metabisulphite (MBS). To investigate whether the effect of frusemide could be mediated through mechanisms other than Na+/K+/Cl- cotransporter inhibition, the effects of amiloride--an inhibitor of sodium channels in the airway epithelium--and of acetazolamide--a specific inhibitor o...

Cl(-) influx across the basolateral membrane is a limiting step in fluid production in exocrine cells and often involves functionally linked Cl(-)/HCO(3)(-) (Ae) and Na(+)/H(+) (Nhe) exchange mechanisms. The dependence of this major Cl(-) uptake pathway on Na(+)/H(+) exchanger expression was examined in the parotid acinar cells of Nhe1(-/-) and Nhe2(-/-) mice, both of which exhibited impaired f...

The dicopper(II) complexes of six pseudo-octapeptides, synthetic analogues of ascidiacyclamide and the patellamides, found in ascidians of the Pacific and Indian Oceans, are shown to be efficient carbonic anhydrase model complexes with kcat up to 7.3 × 10 3 s (uncatalyzed: 3.7 × 10 s; enzyme-catalyzed: 2 × 10–1.4 × 10 s) and a turnover number (TON) of at least 1700, limited only by the experime...

The bicarbonate permeability of the plasma membrane of intact hagfish (Myxine glutinosa) red blood cells and the intracellular carbonic anhydrase activity of these cells were determined by applying the (18)O exchange reaction using a special mass spectrometric technique. When the macromolecular carbonic anhydrase inhibitor Prontosil-Dextran was used to suppress any extracellular carbonic anhydr...

Global change is a major threat to the oceans, as it implies temperature increase and acidification. Ocean acidification (OA) involving decreasing pH and changes in seawater carbonate chemistry challenges the capacity of corals to form their skeletons. Despite the large number of studies that have investigated how rates of calcification respond to ocean acidification scenarios, comparatively fe...

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...