an acyl phosphate + H2O = a carboxylate + H(+) + phosphate Optimum pH is 4.7-5.7. Optimum temperature is 81 degrees Celsius. Thermostable up to 100.8 degrees Celsius. Poorly active at 25 degrees Celsius. Enzymatic activity is increased 4-fold by temperature increase from 25 to 45 degrees Celsius and more than 9-fold at 98 degrees Celsius. Belongs to the acylphosphatase family.