在通过氯化铵变性过程中，D-甘油醛-3-磷酸脱氢酶和果糖-1,6-二磷酸酶的失活先于其别构性质和构象的变化。
Inactivation precedes changes in allosteric properties and conformation of D-glyceraldehyde-3-phosphate dehydrogenase and fructose-1,6-bisphosphatase during denaturation by guanidinium chloride.
作者信息
Jiang R F, Tsou C L
机构信息
National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Beijing, China.
出版信息
Biochem J. 1994 Oct 1;303 ( Pt 1)(Pt 1):241-5. doi: 10.1042/bj3030241.
It has been shown that inactivation of several enzymes precedes overall conformational changes of the enzyme molecules as a whole during denaturation [Tsou (1993) Science, 262, 380-381]. However, the relation between inactivation, loss of allosteric properties of oligomeric enzymes and unfolding of the enzyme molecule during denaturation remain little explored. These have now been compared for D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and fructose-1,6-bisphosphatase (FruP2ase) during denaturation by guanidinium chloride (GdmCl). GAPDH is completely inactivated at 0.3 M GdmCl but at this GdmCl concentration it still binds NAD+ with negative co-operativity. At 0.4 M GdmCl, inactivation of FruP2ase reaches completion whereas its allosteric properties, including the heterotropic effect of AMP inhibition and K+ activation with positive co-operativity, are only partially affected. Much higher GdmCl concentrations are required to bring about unfolding of the overall structures of both enzymes.
研究表明，在变性过程中，几种酶的失活先于整个酶分子的整体构象变化[邹承鲁（1993年），《科学》，262卷，380 - 381页]。然而，在变性过程中，寡聚酶的失活、别构性质的丧失与酶分子展开之间的关系仍鲜有人研究。现在，通过氯化胍（GdmCl）变性处理，已对D - 甘油醛 - 3 - 磷酸脱氢酶（GAPDH）和果糖 - 1,6 - 二磷酸酶（FruP2ase）进行了比较。GAPDH在0.3 M GdmCl时完全失活，但在此GdmCl浓度下，它仍以负协同性结合NAD⁺。在0.4 M GdmCl时，FruP2ase的失活达到完全，但它的别构性质，包括AMP抑制的异促效应和K⁺激活的正协同性，仅受到部分影响。使两种酶的整体结构展开需要更高浓度的GdmCl。
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