尿素使山羊脾脏组织蛋白酶B失活的一种可能机制。展开与重折叠研究。
A probable mechanism of inactivation by urea of goat spleen cathepsin B. Unfolding and refolding studies.
作者信息
Agarwal S K, Khan M Y
机构信息
Department of Biochemistry, School of Life Sciences, North-Eastern Hill University, Shillong, India.
出版信息
Biochem J. 1988 Dec 1;256(2):609-13. doi: 10.1042/bj2560609.
Equilibrium and kinetic studies of the unfolding-refolding of goat spleen cathepsin B induced by urea are reported. Tryptophan fluorescence and enzyme activity were monitored. The activity of cathepsin B is lost reversibly at 1.2 M-urea. The enzyme unfolds in two main stages, having a stable intermediate (Y) between its native (N) and fully denatured (D) states. Enzyme activity and kinetic studies of these transitions indicate the existence of at least two intermediate forms (X1 and X2) between the N and Y states. The overall denaturation and renaturation scheme is thus suggested to be N in equilibrium with X1----X2 in equilibrium with Y in equilibrium with D. The multiplicity of the intermediate and fractional regaining of the activity up to a urea concentration of 2 M indicates the presence of multidomain structure in cathepsin B.
本文报道了尿素诱导山羊脾脏组织蛋白酶B去折叠-再折叠过程的平衡和动力学研究。监测了色氨酸荧光和酶活性。组织蛋白酶B的活性在1.2M尿素浓度下可逆丧失。该酶的去折叠过程主要分为两个阶段，在天然态（N）和完全变性态（D）之间存在一个稳定的中间体（Y）。对这些转变的酶活性和动力学研究表明，在N态和Y态之间至少存在两种中间体形式（X1和X2）。因此，整体的变性和复性模式被认为是N与X1处于平衡，X1转变为X2，X2与Y处于平衡，Y与D处于平衡。中间体的多样性以及在尿素浓度达到2M时活性的部分恢复表明组织蛋白酶B中存在多结构域结构。
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