A variant of one form of red cell carbonic anhydrase was discovered in "Chamorro" inhabitants from the islands of Guam and Saipan. Segregation of this trait in four pedigrees indicates that it is under the control of a single autosomal gene.

Now, some 55 years after its discovery in bovine red cells, carbonic anhydrase (CA), in all its varied forms, continues to challenge and intrigue physiologists, biochemists and molecular geneticists. This is so because of an increasing awareness of the many apparently diverse functions of the different CA isozymes encoded by this large multigene family, the continuing discovery of new CA, or CA...

Functional constraints on proteins limit their evolutionary rates at specific sites. These constraints allow for the interpretation of conserved residues and sites with a rate change as those most likely underlying the functional similarities and differences among protein subfamilies, respectively. This study describes new likelihood-ratio tests (LRTs) that complement existing ones for the iden...

Recombinant beta-carbonic anhydrase from the garden pea, Pisum sativum, was purified to homogeneity and crystallized. Crystals belong to the orthorhombic space group C222, with unit-cell parameters a = 136.3, b = 142.5, c = 201.4 A, alpha = beta = gamma = 90 degrees. Crystals typically diffracted anisotropically, with a maximal resolution of 2.0 A in the strongest direction. The calculated Matt...

Ocean acidification is altering the oceanic carbonate saturation state and threatening the survival of marine calcifying organisms. Production of their calcium carbonate exoskeletons is dependent not only on the environmental seawater carbonate chemistry but also the ability to produce biominerals through proteins. We present shell growth and structural responses by the economically important m...

The carbonic anhydrase activity of human platelets was investigated by measuring the kinetics of CO2 hydration in supernatants of platelet lysates by using a pH stopped-flow apparatus. An average carbonic anhydrase concentration of 2.1 microM was determined for pellets of human platelets. Analysis of the kinetic properties of this carbonic anhydrase yielded a Km value of 1.0 mM, a catalytic-cen...

The mechanism of Pb-induced disruption of Na(+) and Cl(-) balance was investigated in the freshwater rainbow trout (Oncorhynchus mykiss). Na(+) and Cl(-) influx rates were reduced immediately in the presence of 2.40 +/- 0.24 and 1.25 +/- 0.14 muM Pb, with a small increase in efflux rates occurring after 24-h exposure. Waterborne Pb caused a significant decrease in the maximal rate of Na(+) infl...

Two isozymes of carbonic anhydrase (EC 4.2.1.1.) were compared in the anterior pituitary gland of non-tumor-bearing rats and in the hormone-secreting pituitary tumors. In contrast to the pituitary gland, which contained 60 to 70% of the total carbonic anhydrase in the particulate subcellular fraction, three hormone-secreting pituitary tumors were devoid of the particulate (Triton X-100-solubili...

Hemolymph osmolality, and changes in gill carbonic anhydrase (CA) activity, relative mRNA expression, and CA protein concentration were measured in the green crab Carcinus maenas acclimated to 32 ppt salinity and transferred to 10 ppt. Hemolymph osomolality stabilized at new, acclimated values, by 24 hr after transfer. There was a large increase in CA mRNA concentrations, as measured by quantit...

According to current concepts, acidification of the urine in the distal tubule and final removal of bicarbonate from the glomerular filtrate occur by a process of ion exchange in which hydrogen ions within tubular cells are exchanged for sodium in the filtrate (1). It is thought that carbonic anhydrase catalyzes an essential reaction which either directly supplies hydrogen ions to the exchange ...