JACK BEAN UREASE (EC 3.5.1.5) . DEMONSTRATION OF A CARBAMOYL-TRANSFER REACTION AND INHIBITION BY NYDROXAMIC ACIDS

A carbamoyl-transfer reaction has been demonstrated in the urease-catalyzed hydrolysis of urea, using a thymol blue buffer to give a sensitive spectrophotometric measure of acidity changes. This demonstration offers further support for the proposition that carbamate is the first product of the urease-catalyzed hydrolysis of urea. The inhibition of urease by acetohydroxamic acid and chloroacetohydroxamic acid has been studied from both directions and found to be completely reversible. Hydroxyurea, itself a substrate, shows a time-dependent inhibition, completely reversible on consumption of hydroxyurea. Electron microscopy suggests that there are six subunits per 483,000 molecular weight species. © 1969, American Chemical Society. All rights reserved.