Li L, Lange A J, Pilkis S J
Department of Physiology and Biophysics SUNY, Stony Brook 11794.
Biochem Biophys Res Commun. 1993 Jan 29;190(2):397-405. doi: 10.1006/bbrc.1993.1061.
A chicken liver cDNA for 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase was isolated from a Lambda ZAP2 phage library. The chicken liver cDNA codes for a protein that has 89.1, 88.4 and 88.0% amino acid identity with the human, rat and bovine liver isoforms, respectively. The kinetic properties of the rat and chicken liver enzymes, purified to homogeneity after expression in E. coli, were different including negative cooperativity for ATP binding and inhibition by Mg2+ for the chicken liver 6-phosphofructo-2-kinase but not for the rat liver kinase. Differences in the beta-loop ATP signature sequences in the chicken and rat liver kinase domains may explain the kinetic differences and represent the major divergence in the evolution of the enzyme from birds to mammals.
从λZAP2噬菌体文库中分离出鸡肝6-磷酸果糖-2-激酶/果糖-2,6-二磷酸酶的cDNA。鸡肝cDNA编码的蛋白质与人类、大鼠和牛肝同工型的氨基酸同一性分别为89.1%、88.4%和88.0%。在大肠杆菌中表达后纯化至同质的大鼠和鸡肝酶的动力学特性不同，包括鸡肝6-磷酸果糖-2-激酶对ATP结合具有负协同性且受Mg2+抑制，而大鼠肝激酶则不然。鸡和大鼠肝激酶结构域中β-环ATP特征序列的差异可能解释了动力学差异，并代表了该酶从鸟类到哺乳动物进化过程中的主要分歧。
