The Kinetics of Urease Activity in Corynebacterium renale

SUMMARY: The urease activity of Corynebacterium renale has been studied in washed suspensions and in cell-free extracts of the micro-organism. The urease is constitutive, and whole organisms have a urease activity of 17,000-22,000μg. NH3/mg. dry wt. organisms/hr. in 0·5m-urea in phosphate buffer at pH 7·0. In a cell-free extract the enzyme is optimally active at pH 7·5, has a Michaelis constant of 0·030m, and a temperature velocity constant of 7800 cal.; the activity is inhibited by atmospheric oxygen and by thiourea, but not by sixteen other analogues of urea tested.