Comparison of blood carbonic anhydrase activity of athletes performing interval and continuous running exercise at high altitude.

The effects of high-intensity interval and continuous exercise on erythrocytes carbonic anhydrase (CA, EC 4.2.1.1) activity levels were scarcely investigated up until now. Here we present a study focused on the CA activity from erythrocytes of athletes experiencing interval and continuous training for 6 weeks, during cold weather and at high altitude (> 1600 m). We observed a 50% increase in the blood CA activity at the second week after initiation of the training in both interval and continuos running groups, whereas the control group did not experience any variation in the enzyme activity levels. In the trained individuals a mild decrease in their body mass, BMI and an increased [Formula: see text] were also observed. The CA activity returned at the basal values after 4-6 weeks after the training started, probably proving that a metabolic compensation occurred without the need of an enhanced enzyme activity. The unexpected 50% rise of activity for an enzyme which acts as a very efficient catalyst for CO2 hydration/bicarbonate dehydration, such as the blood CA, deserves further investigations for better understanding the physiologic basis of this phenomenon.

Purification and characterization of carbonic anhydrase from Agri Balik Lake trout gill (Salmo trutta labrax) and effects of sulfonamides on enzyme activity.

Carbonic anhydrase (CA) was purified from Agri Balik Lake trout gill (fCA) by affinity chromatography on a sepharose 4B-tyrosine-sulfanilamide column. The fCA enzyme was purified with about a 303.9 purification factor, a specific activity 4130.4 EU (mg-protein)(-1), and a yield of 79.3 by using sepharose-4B-L tyrosine-sulfanilamide affinity gel chromatography. The molecular weight determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was found to be about 29.9 kDa. The kinetic parameters, K(M) and V(max) were determined for the 4-nitrophenyl acetate hydrolysis reaction. Some sulfonamides were tested as inhibitors against the purified CA enzymes. The Ki constants for mafenide (1), p-toluenesulfonamide (2), 2-bromo-benzene sulfonamide (3), 4-chlorobenzene sulfonamide (4), 4-amino-6-chloro-1-3 benzenedisulfonamide (5), sulfamethazine (6), sulfaguanidine (7), sulfadiazine (8), and acetozazolamide (9) were in the range of 7.5-108.75 µM.