We have cloned, purified and characterized the gamma-carbonic anhydrase (CA, EC 4.2.1.1) present in the genome of the Antarctic bacterium Colwellia psychrerythraea, which is an obligate psychrophile. The enzyme shows a significant catalytic activity for the physiologic reaction of CO2 hydration to bicarbonate and protons, with the following kinetic parameters: k(cat) of 6.0 x 10(5) s(-1) and a k(cat)/K-m of 4.7 x 10(6) M-1 x s(-1). This activitywas inhibited by the sulfonamide CA inhibitor (CAI) acetazolamide, with a K-I of 502 nM. A range of anions was also investigated for their inhibitory action against the new enzyme CpsCA. Perchlorate, tetrafluoroborate, fluoride and bromide were not inhibitory, whereas cyanate, thiocyanate, cyanide, hydrogensulfide, carbonate and bicarbonate showed K(I)s in the range of 1.4-4.4 mM. Diethyldithiocarbamate was a better inhibitor (K-I of 0.58 mM) whereas sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid were the most effective inhibitors detected, with K(I)s ranging between 8 and 38 mu M. The present study may shed some more light regarding the role that gamma-CAs play in the life cycle of psychrophilic bacteria as the Antarctic one investigated here. (c) 2016 Elsevier Ltd. All rights reserved.

Cloning, characterization and anion inhibition studies of a gamma-carbonic anhydrase from the Antarctic bacterium Colwellia psychrerythraea

Del Prete Sonia;Carginale Vincenzo;Capasso Clemente
2016

Abstract

We have cloned, purified and characterized the gamma-carbonic anhydrase (CA, EC 4.2.1.1) present in the genome of the Antarctic bacterium Colwellia psychrerythraea, which is an obligate psychrophile. The enzyme shows a significant catalytic activity for the physiologic reaction of CO2 hydration to bicarbonate and protons, with the following kinetic parameters: k(cat) of 6.0 x 10(5) s(-1) and a k(cat)/K-m of 4.7 x 10(6) M-1 x s(-1). This activitywas inhibited by the sulfonamide CA inhibitor (CAI) acetazolamide, with a K-I of 502 nM. A range of anions was also investigated for their inhibitory action against the new enzyme CpsCA. Perchlorate, tetrafluoroborate, fluoride and bromide were not inhibitory, whereas cyanate, thiocyanate, cyanide, hydrogensulfide, carbonate and bicarbonate showed K(I)s in the range of 1.4-4.4 mM. Diethyldithiocarbamate was a better inhibitor (K-I of 0.58 mM) whereas sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid were the most effective inhibitors detected, with K(I)s ranging between 8 and 38 mu M. The present study may shed some more light regarding the role that gamma-CAs play in the life cycle of psychrophilic bacteria as the Antarctic one investigated here. (c) 2016 Elsevier Ltd. All rights reserved.
2016
Istituto di Bioscienze e Biorisorse
Carbonic anhydrase
Metalloenzymes
Inhibitors
Anions
Psychrophiles
Hydratase activity
Antarctic carbonic anhydrase
Cold adaptation
Cold-enzymes
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/316598
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