Investigations of the esterase, phosphatase, and sulfatase activities of the cytosolic mammalian carbonic anhydrase isoforms I, II, and XIII with 4-nitrophenyl esters as substrates.
The esterase, phosphatase, and sulfatase activities of carbonic anhydrase (CA, EC 4.2.1.1) isozymes, CA I, II, and XIII with 4-nitrophenyl esters as substrates was investigated. These enzymes show esterase activity with 4-nitrophenyl acetate as substrate, with second order rate constants in the range of 753-7706M(-1)s(-1), being less effective as phosphatases (k(cat)/K(M) in the range of 14.89-1374.40M(-1)s(-1)) and totally ineffective sulfatases. The esterase/phosphatase activities were inhibited by sulfonamide CA inhibitors, proving that the zinc-hydroxide mechanism responsible for the CO(2) hydrase activities of CAs is also responsible for their esterase/phosphatase activity. CA XIII was the most effective esterase and phosphatase. CA XIII might catalyze other physiological reactions than CO(2) hydration, based on its relevant phosphatase activity.
Innocenti
Alessio
A
Universita degli Studi di Firenze, Laboratorio di Chimica Bioinorganica, Rm. 188, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Firenze, Italy.
Scozzafava
Andrea
A
Parkkila
Seppo
S
Puccetti
Luca
L
De Simone
Giuseppina
G
Supuran
Claudiu T
CT
D024401:Carbonic Anhydrase I / Q000378:metabolism; D024402:Carbonic Anhydrase II / Q000378:metabolism; D002256:Carbonic Anhydrases / Q000378:metabolism*; D002384:Catalysis; D003600:Cytosol / Q000201:enzymology*; D004950:Esterases / Q000378:metabolism*; D004952:Esters / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D009596:Nitrophenols / Q000737:chemistry / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D013379:Substrate Specificity; D013429:Sulfatases / Q000378:metabolism*
D004952:Esters; D007527:Isoenzymes; D009596:Nitrophenols; D004950:Esterases; D010744:Phosphoric Monoester Hydrolases; D013429:Sulfatases; D024401:Carbonic Anhydrase I; D024402:Carbonic Anhydrase II; C483903:CA13 protein, human; D002256:Carbonic Anhydrases; C024836:4-nitrophenol