Aerobacter aerogenes PRL-R3 urease. Purification and properties

A method for the preparation of a 150-fold purified and homogenous A. aerogenes urease is reported. The enzyme exhibited two pH optima at pH 7.0 and 7.5 in triethanolamine and phosphate buffer, respectively. The affinity of the enzyme toward its substrate increased with the increase of pH. No effect of the pH was observed on the measured temperature coefficient (Q10). There was no discontinuity in the Arrhenius plots at pH 5.4 and 7.5 but an upward discontinuity at pH 6.15 and 8.7 with transition temperature at 30 degrees C. Also, the calculated activation energies are greatly affected by the pH of the enzyme reaction mixture.