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pubmed:abstractText |
Carbonic anhydrases (CAs, EC 4.2.1.1) belonging to ?-, ?-, ?- and ?-classes and from various organisms, ranging from the bacteria, archaea to eukarya domains, were investigated for their esterase/phosphatase activity with 4-nitrophenyl acetate, 4-nitrophenyl phosphate and paraoxon as substrates. Only ?-CAs showed esterase/phosphatase activity, whereas enzymes belonging to the ?-, ?- and ?-classes were completely devoid of such activity. Paraoxon, the metabolite of the organophosphorus insecticide parathione, was a much better substrate for several human/murine ?-CA isoforms (CA I, II and XIII), with k(cat)/K(M) in the range of 2681.6-4474.9M(-1)s(-1), compared to 4-nitrophenyl phosphate (k(cat)/K(M) of 14.9-1374.4M(-1)s(-1)).
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pubmed:affiliation |
Università degli Studi di Firenze, Polo Scientifico, Laboratorio di Chimica Bioinorganica, Rm. 188, Via della Lastruccia 3, 50019 Sesto Fiorentino (Florence), Italy.
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