Dzugaj A, Buczyłko J
Institute of Organic and Physical Chemistry, Technical University of Wrocław, Poland.
Acta Biochim Pol. 1987;34(4):441-50.
Denaturation of fructose-1,6-bisphosphatase (Fru-P2-ase, EC 3.1.3.11) by urea and renaturation of denatured enzyme has been investigated. Denaturation lowers the specific activity of the enzyme but even at 8 M urea concentration in the presence of sucrose the activity of the enzyme is detectable. Centrifugation of the enzyme in a sucrose density gradient at 4 M urea reveals one peak of protein corresponding to a dimer. Denaturation increases intensity of intrinsic fluorescence of Fru-P2-ase and causes a red shift of fluorescence peak of the thioisoindole derivative of the enzyme. Renaturation of the denatured enzyme followed as the reappearance of enzymatic activity in the presence and absence of bovine serum albumin (BSA) is characterised by first order kinetics, k = 1.78 X 10(-3) s-1. The presence of BSA does not affect the rate of renaturation but perceptibly increases the recovery of enzymatic activity. A 100% recovery of Fru-P2-ase activity is observed at 0.5 micrograms/mL concentration of the enzyme and 2 mg/mL of BSA.
研究了尿素对果糖-1,6-二磷酸酶（Fru-P2-ase，EC 3.1.3.11）的变性作用以及变性酶的复性情况。变性作用降低了该酶的比活性，但即使在8M尿素浓度且存在蔗糖的情况下，仍可检测到该酶的活性。在4M尿素条件下，将该酶在蔗糖密度梯度中进行离心，发现一个对应二聚体的蛋白质峰。变性作用增强了Fru-P2-ase的内源荧光强度，并导致该酶的硫代异吲哚衍生物的荧光峰发生红移。变性酶的复性表现为在有和没有牛血清白蛋白（BSA）存在的情况下酶活性的重新出现，其特征符合一级动力学，k = 1.78×10^(-3) s^(-1)。BSA的存在不影响复性速率，但明显提高了酶活性的恢复率。在酶浓度为0.5微克/毫升和BSA浓度为2毫克/毫升时，观察到Fru-P2-ase活性有100%的恢复。
