Prakash O, Bhushan G
Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi, India.
J Enzyme Inhib. 1998 Feb;13(1):69-77. doi: 10.3109/14756369809035828.
Urease from seeds of the water melon was found to be inhibited by various salts of sodium. Sodium fluoride strongly inhibited the activity in the low urea concentration range. The enzyme was also inhibited by a high concentration of urea which was completely abolished in the presence of 10 mM sodium fluoride. Time-dependent inactivation of urease with iodoacetic acid, N-ethylmaleimide and p-hydroxymercuribenzoate exhibited biphasic kinetics in which half of the initial activity was lost in the fast phase and the remainder in a slow phase. Each phase exhibited first-order kinetics. These observations are suggestive of the existence of half-and-half distribution of sites.
研究发现，西瓜种子中的脲酶会受到各种钠盐的抑制。氟化钠在低尿素浓度范围内强烈抑制其活性。该酶也会受到高浓度尿素的抑制，而在10 mM氟化钠存在的情况下，这种抑制作用会完全消除。脲酶与碘乙酸、N-乙基马来酰亚胺和对羟基汞苯甲酸的时间依赖性失活呈现双相动力学，其中在快速阶段损失了一半的初始活性，其余的在缓慢阶段损失。每个阶段都呈现一级动力学。这些观察结果表明存在位点的对半分布。
