Wedler F C, McLean M A
Department of Molecular and Cell Biology, Althouse Laboratory, Pennsylvania State University, University Park 16802.
Biochim Biophys Acta. 1991 Jan 8;1076(1):161-3. doi: 10.1016/0167-4838(91)90235-r.
Glutamine synthetase is expressed in Bacillus caldolyticus as two isoforms that differ in physico-chemical and regulatory properties. Biphasic kinetics of thermal denaturation of E-I and E-II (Merkler, D.J., et al (1987) Biochemistry 26, 7805), suggested the formation of intermediates. CD spectral changes of E-II induced by guanidine-HC1 clearly indicate a three-state pathway for unfolding (N----I----D). Refolding of E-II from 6 M GuHCl led to only 15% recovery of activity, compared to greater than or equal to 90% with E-I.
谷氨酰胺合成酶在嗜热芽孢杆菌中以两种同工型表达，它们在物理化学和调节特性上有所不同。E-I和E-II热变性的双相动力学（Merkler, D.J.等人，(1987)《生物化学》26, 7805）表明形成了中间体。盐酸胍诱导的E-II的圆二色光谱变化清楚地表明了一种三态去折叠途径（N→I→D）。与E-I大于或等于90%的活性恢复相比，从6 M盐酸胍中复性的E-II的活性仅恢复了15%。
