Acid phosphatases are enzymes widespread in nature that hydrolyze phosphomonoesters at pH 5,0; this reaction yields alcohol and inorganic phosphate. Comparison of bovine, alpaca and porcine liver phosphatases kcat/Km values suggests these enzymes have a high affinity for p-nitrophenyl phosphate substrate. Products that are released during acid phosphatase catalysis show that phenol or p-nitrophenol behave as non competitive inhibitors, whereas inorganic phosphate shows competitive inhibition. Different nucleophiles more efficient than water have been used, such as methanol, ethanol and glycerol, showing the probable formation of a covalent complex in the catalytic sequence. Modifications produced in Km and Vmax values as well as in the reaction released products suggest the development of an enzyme-phosphate complex. pH affects acid phosphatases Km and Vmax values. Behavioral analysis of...

Objective: To determine the effect of glycerol on hydrolisis of p-nitrophenyl phosphate at pH 5,0 by low molecular weight acid phosphatase from alpaca liver. Design: Experimental analytical study. Setting: Biochemistry and Nutrition Research Center, Faculty of Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru. Materials: Disodic p-nitrophenyl phosphate salt, glacial acetic acid, glycerol, tricloroacetic acid, sulfuric acid, ammonium molibdate, ascorbic acid, ammonium sulphate, sephadex G-75 (45-120), sulpho ethyl sephadex C-50 and ethylene diaminotetraacetic (EDTA) chemical reactives. Methods: Both Km and Vmax kinetic parameters were determined with p-nitrophenyl phosphate as substrate in presence of different concentrations of glycerol. The rate of formation of products was determined as a function of the concentration of such nucleophile. Main outcome measures: Glycerol ef...