Pontremoli S, Melloni E, De Flora A, Horecker B L
Proc Natl Acad Sci U S A. 1973 Mar;70(3):661-4. doi: 10.1073/pnas.70.3.661.
Removal of the NH(2)-terminal region of fructose 1,6-bisphosphatase from rabbit liver by digestion with subtillisin, or changes in conformation in this region of the protein produced by exposure to low concentrations of urea, result in similar changes in catalytic and allosteric properties of the enzyme. These changes include shift of the pH optimum to more alkaline pH, and loss of sensitivity to inhibition by AMP. The conformation changes are monitored by changes in the fluorescence of the single tryptophan residue, which is located near the NH(2)-terminus. Thus, the tryptophan-containing peptide appears to determine the functional properties of the native enzyme.
用枯草杆菌蛋白酶消化去除兔肝果糖1,6 -二磷酸酶的NH(2)-末端区域,或通过暴露于低浓度尿素使该蛋白质区域的构象发生变化,都会导致该酶的催化和别构性质发生类似变化。这些变化包括最适pH向更碱性的pH偏移,以及对AMP抑制的敏感性丧失。构象变化通过位于NH(2)-末端附近的单个色氨酸残基荧光的变化来监测。因此,含色氨酸的肽段似乎决定了天然酶的功能特性。