1. A method is described for measuring accurately the initial velocity of the hydration reaction catalysed by the enzyme carbonic anhydrase (EC 4.2.1.1); the method depends on the titration of H(+) ions at constant pH. 2. Human erythrocyte carbonic anhydrase, isoenzyme C, was used to illustrate the method. Under the experimental conditions employed (0 degrees , pH7.0, in the presence of 45mm-so...

Investigations of the rapid enzyme carbonic anhydrase have now been extended by crystallographic analysis at high CO2 pressures to examine the movements of water molecules in different steps of the catalysis. The rate of catalysis seems well explained by the assembled observations.

Diabetes-associated complications in the microvasculature of the brain are caused by oxidative stress, generated by overproduction of reactive oxygen species from hyperglycemia-induced accelerated oxidative metabolism of glucose. Pericytes, essential for the viability of the microvasculature, are especially susceptible to oxidative stress. Mitochondrial carbonic anhydrases, regulators of the ox...

mantle coincided with the time when the greatest shell shoot was measured (Table 1, day 40). Our results support the view that, at least in mantle tissue, there is a direct correlation between shell formation and carbonic anhydrase activity. A major function of the gill is gaseous exchange, and the fact that gill carbonic anhydrase activity follows a similar pattern of change to that of new she...

The temperature dependence of the activity and structure of the enzyme carbonic anhydrase was studied. The Arrhenius plot shows a jump which is seen usually in proteins with more than one subunit or with one subunit but more than one domain. Since carbonic anhydrase has only one subunit with one domain, the fine conformational changes of the protein motifs could only be detected through circula...

The primary structure of human erythrocyte carbonic anhydrase C has been determined. The single polypeptide chain contains 259 amino acid residues devoid of disulfide bridges. The experimental approach has involved restriction of the action of trypsin to arginyl bonds by amidination of the lysyl side chains. The six tryptic fragments obtained have been separated and sequenced by manual techniqu...

Carbonic anhydrase, a zinc enzyme catalyzing the interconversion of carbon dioxide and bicarbonate, is nearly ubiquitous in the tissues of highly evolved eukaryotes. Here we report on the first known plant-type (b-class) carbonic anhydrase in the archaea. The Methanobacterium thermoautotrophicum DH cab gene was hyperexpressed in Escherichia coli, and the heterologously produced protein was puri...

Carbonic anhydrase, a zinc enzyme catalyzing the interconversion of carbon dioxide and bicarbonate, is nearly ubiquitous in the tissues of highly evolved eukaryotes. Here we report on the first known plant-type (beta-class) carbonic anhydrase in the archaea. The Methanobacterium thermoautotrophicum DeltaH cab gene was hyperexpressed in Escherichia coli, and the heterologously produced protein w...