Binding of terbium (III) to yeast enolase.
Binding of terbium (III) to yeast enolase.
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铽 (III) 与酵母烯醇化酶的结合。
DOI：
10.1016/s0162-0134(00)80012-4
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发表时间：
1981
影响因子：
3.9
通讯作者：
Elliott,JI
中科院分区：
文献类型：
--
作者：
Brewer,JM;Carreira,LA;Irwin,RM;Elliott,JI
几个独立的标准表明，在没有底物-酶和金属荧光滴定的情况下，2摩尔的Tb(III)与酵母烯醇化酶结合，对热稳定性的影响，以及已发表的超滤和抑制实验。这些测量还表明，Tb的结合位置与通常由“构象”镁占据的位置相同。然而，Tb的结合比镁强得多，加入过量EDTA后，Tb酶的吸光度变化动力学的测量表明，Tb酶的解离常数约为镁酶的1500。酶活性随底物浓度变化的测量表明，Tb不允许酶活性。然而，如果底物类似物3-氨基烯醇式丙酮酸2-磷酸(AEP)存在，镁就能更有效地与稀土元素竞争。在280 nm激发下，稀土元素的荧光不容易被观察到，这表明在金属的配位球体中没有酪氨酸或色氨酸。用Ar离子激光的488 nm辐射激发Tb表明，金属的荧光通过与酶的结合而增强。EDTA和碳酸盐具有相似的效果。这表明羧基参与了酵母烯醇化酶构象部位的金属结合。在D2O存在和不存在的情况下，对酶结合的Tb的寿命的测量表明，与所使用的缓冲液无关，每个结合的金属上仍有三个摩尔的水。如果酶结合的Tb被认为是九配位的，那么金属必须从酶中结合到六个基团。底物的存在不会显著影响结合的Tb的发射光谱或金属上残留的水分子的数量，但量热测量表明底物与Tb酶结合。
Several independent criteria indicate 2 mol of terbium (III) bind to yeast enolase in the absence of substrate-fluorescence titrations of enzyme and metal, effects on thermal stability and published ultrafiltration and inhibition experiments. These measurements also suggest the terbium binding sites are the same as those normally occupied by “conformational” magnesium. Terbium binds much more strongly than magnesium, however, and measurements of the kinetics of the absorbance change in the terbium-enzyme on adding excess EDTA suggest the terbium-enzyme dissociation constant is about 1 500 that of the magnesium-enzyme. Measurements of enzyme activity as a function of substrate concentration show that terbium permits no enzymatic activity. However, magnesium competes more effectively with the lanthanide if the substrate analogue 3-aminoenolpyruvate 2-phosphate (AEP) is present. The fluorescence of the lanthanide is not readily observed on exciting the terbium-enzyme at 280 nm, indicating the absence of tyrosines or tryptophans in the coordination sphere of the metal. Excitation of terbium using 488 nm radiation from an argon ion laser shows the fluorescence of the metal is enhanced by binding to the enzyme. EDTA and carbonate have similar effects. This suggests carboxyl groups are involved in binding metal at the conformational sites of yeast enolase. Measurements of lifetimes of enzyme-bound terbium in the presence and absence of D 2 O indicated three moles of water remained on each of the bound metals, independently of the buffer used. If enzyme-bound terbium is assumed to be nine-coordinate, the metal must bind to six groups from the enzyme. The presence of substrate does not markedly affect the emission spectrum of the bound terbium or the number of water molecules remaining on the metal, but calorimetric measurements show that substrate binds to the terbium enzyme.
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两种高亲和力烯醇化酶抑制剂的研究。
影响因子：
2.9
作者：
T. Spring;F. Wold
通讯作者：
F. Wold
抑制性金属与酵母烯醇酶的结合。
影响因子：
3.9
作者：
J. Elliott;J. Brewer
通讯作者：
J. Brewer
研究催化和构象金属在酵母烯醇酶产生酶活性中的作用。
影响因子：
3.9
作者：
J. Brewer;K. M. Collins
通讯作者：
K. M. Collins
镁对酵母烯醇酶某些物理性质的影响。
DOI：
10.1016/s0021-9258(18)96574-9
发表时间：
1966
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
J. Brewer;G. Weber
通讯作者：
G. Weber
结合镁离子后酵母烯醇酶直接测量质子释放
影响因子：
3.5
作者：
L. Faller;A. Johnson
通讯作者：
A. Johnson