Innocenti Alessio, Scozzafava Andrea, Parkkila Seppo, Puccetti Luca, De Simone Giuseppina, Supuran Claudiu T
Universita degli Studi di Firenze, Laboratorio di Chimica Bioinorganica, Rm. 188, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Firenze, Italy.
Bioorg Med Chem Lett. 2008 Apr 1;18(7):2267-71. doi: 10.1016/j.bmcl.2008.03.012. Epub 2008 Mar 7.
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.
以4-硝基苯酯为底物，研究了碳酸酐酶（CA，EC 4.2.1.1）同工酶CA I、II和XIII的酯酶、磷酸酶和硫酸酯酶活性。这些酶以4-硝基苯乙酸为底物时表现出酯酶活性，二级速率常数在753-7706M⁻¹s⁻¹范围内，作为磷酸酶时活性较低（kcat/KM在14.89-1374.40M⁻¹s⁻¹范围内），而作为硫酸酯酶则完全无活性。酯酶/磷酸酶活性受到磺胺类CA抑制剂的抑制，这证明负责CA的CO₂水合酶活性的锌-氢氧化物机制也负责其酯酶/磷酸酶活性。CA XIII是最有效的酯酶和磷酸酶。基于其相关的磷酸酶活性，CA XIII可能催化除CO₂水合反应之外的其他生理反应。
