A Study on Esterase Activity of Carbonic Anhydrase from Van Lake Fish (Calcalburnus tarichi)

Authors : Haluk TESTERECİ

Pages : 145-154

View : 17 | Download : 11

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :No study has been reported on carbonic anhydrase enzyme of the fish insert ignore into journalissuearticles values(Calcalburnus tarichi); living in the carbonated Van Lake. Having partial purification of Carbonic anhydrase from gill and liver of Van Lake fish by ethanol-chloroform and acetone-chloroform, the esterase activity was performed by using p-nitrophenyl acetate as a substrate on spectrophotometer. The effects of the some kinetic parameters insert ignore into journalissuearticles values(km, Vo, Vmax, Na2CO3 activation, optimum pH etc.); have been examined When Lineweaver-Burk diagram of liver extracts insert ignore into journalissuearticles values(at 25°C); is examined, ethanol has an apparent competitive inhibition compare to acetone extracts. So Km of the substrate insert ignore into journalissuearticles values(p-nitrophenyl acetate); is 0.95 mM is for ethanol extract and 0.54 mM of that is found for acetone extracts. In two extracts from gill insert ignore into journalissuearticles values(at 25°C);, ethanol seems to have a non-competitive inhibition comparing to acetone, Km for both extracts is 0.39 mM. Na+/CO32- ions induce esterase activity, Na+/CO3-2 ions are not competitive with the inhibitory effects of ethanol. Infect, inhibition of ethanol on gill esterase activity appears to be competitive which is understood by addition of Na+/CO3-2. Since carbonate ions and p-nitrophenyl acetate act on two different catalytic site of this enzyme, both have formed a cooperative effect It is clear that carbonic anhydrase activity has not been affected till pH:7.4. Although pH above 8.0 enzyme activity has seem to increase, this increase is due to kinetic reaction between substrate insert ignore into journalissuearticles values(p-nitropheny acetate); and buffer at pH:8-11.5. So, the esterase activity of this enzyme at this high pH, can not be evaluated. for the esterase activity of this enzyme. The optimal and unaffected pH for the substrate is 7 for the esterase activity of carbonic anhydrase. `Esterase` activity could be useful for determining `anhydrase` activity of Carbonic anhydrase enzyme of Van Lake fish. Stimulation of esterase activity of carbonic anhydrase has been shown by addition of CO32- ions. Carbonic anhydrase present in gill and liver of Van Lake fish has a significant regulatory role for internal pH balance.
Keywords : Carbonic anhydrase, Van Lake fish, esterase activity