Competitive inhibitors of free and chitosan-immobilized urease.

The influence of four inhibitors: boric acid, thioglycolic acid, sodium fluoride and acetohydroxamic acid on the activity of urease, both in the native form and immobilized covalently on glutaraldehyde-pretreated chitosan membrane, was studied. Urea hydrolysis was carried out in phosphate buffer, pH 7, at 25 degrees C at urea concentration of 50 mM. The immobilized urease was more resistant than the native one to the action of all the investigated inhibitors, except boric acid. This property of the enzyme offers a possibility of its practical application.