Kalckar H M
Biochimie. 1976;58(1-2):81-5. doi: 10.1016/s0300-9084(76)80358-6.
The periplasmic galactose receptor protein of E. coli is the common macromolecule in the initiation of two functions, chemotaxis and active transport. The substrates are glucose and galactose and the affinity for binding to the receptor protein is high (Kp -2 X 10(-8) M for glucose and 1 X 10(-7) M for galactose). A second binding site shows a 100-fold lower affinity. The high concentration of the galactose receptor protein in the periplasmic space tends to give retention through recapture of the ligands. The kinetic properties of the galactose receptor protein are, in general, in harmomy with the kinetics of chemotactic responses to spatial or temporal sugar gradients.
大肠杆菌的周质半乳糖受体蛋白是启动趋化作用和主动运输这两种功能的常见大分子。其底物为葡萄糖和半乳糖，与受体蛋白结合的亲和力很高（葡萄糖的Kp为2×10⁻⁸M，半乳糖的Kp为1×10⁻⁷M）。第二个结合位点的亲和力低100倍。周质空间中高浓度的半乳糖受体蛋白倾向于通过重新捕获配体来实现保留。一般来说，半乳糖受体蛋白的动力学特性与对空间或时间糖梯度的趋化反应动力学相协调。
