Liou R S, Anderson S R
Biochemistry. 1978 Mar 21;17(6):999-1004. doi: 10.1021/bi00599a009.
The binding of 1,N6-ethenoadenosine triphosphate (eATP) to rabbit muscle phosphofructokinase has been studied by fluorescence and circular dichroism, and compared with that of its counterpart, ATP. Muscle phosphofructokinase binds 11.3 +/- 1.2 mol of epsilonATP per tetramer with an average dissociation constant of 60 micrometer. This is in aggreement with the report of 3 ATP binding sites per phosphofructokinase protomer (Kemp & Krebs, 1967). The binding of epsilonATP is relatively homogeneous in comparison with the biphasic binding of ATP. Saturating concentrations of ATP, GTP, and ADP displace about 80% of the bound epsilonATP from the enzyme, whereas FruP2 and AMP displace only 27%. Citrate, on the other hand, enhances the affinity of phosphofructokinase for epsilonATP. The effects of the binding of ATP and epsilonATP on the conformation of enzyme have also been compared. Binding of ATP results in increases in both the lcoal rigidity and the ellipicity of the tryptophanyl side chains, whereas binding of epsilonATP causes a slight decrease in the local rigidity and has virtually no effect on the ellipticity.
通过荧光和圆二色性研究了1,N6-乙烯基三磷酸腺苷（eATP）与兔肌肉磷酸果糖激酶的结合，并与相应的ATP进行了比较。肌肉磷酸果糖激酶每个四聚体结合11.3±1.2摩尔的ε-ATP，平均解离常数为60微米。这与每个磷酸果糖激酶原体有3个ATP结合位点的报道一致（Kemp和Krebs，1967）。与ATP的双相结合相比，ε-ATP的结合相对均匀。ATP、GTP和ADP的饱和浓度可使约80%结合的ε-ATP从酶上解离，而FruP2和AMP仅能解离27%。另一方面，柠檬酸可增强磷酸果糖激酶对ε-ATP的亲和力。还比较了ATP和ε-ATP结合对酶构象的影响。ATP的结合导致色氨酸侧链的局部刚性和椭圆率增加，而ε-ATP的结合导致局部刚性略有下降，对椭圆率几乎没有影响。
