Senior A E, al-Shawi M K, Urbatsch I L
Department of Biochemistry, University of Rochester Medical Center, New York 14642, USA.
J Bioenerg Biomembr. 1995 Feb;27(1):31-6. doi: 10.1007/BF02110328.
ATPase activity of multidrug-resistance protein (P-glycoprotein, Pgp) from Chinese hamster ovary cells was studied. Catalytic characteristics were established for Pgp both in its natural plasma membrane environment and in purified reconstituted protein. Generally the two preparations of Pgp behaved similarly, and demonstrated low affinity for MgATP, low nucleotide specificity, preference for Mg-nucleotide, and pH optimum near 7.5. A high-affinity binding site involved in catalysis was not apparent. Effective covalent inactivators were NBD-C1, NEM, 8-azido-ATP, and 2-azido-ATP. DCCD, FITC, and pyridoxal phosphate were only weakly inhibitory. Lipid composition was found to affect the degree of drug stimulation of ATPase in purified reconstituted Pgp, suggesting that the lipid environment affects coupling between drug-binding and catalytic sites, and that Pgp expressed in different tissues could show different functional characteristics.
研究了中国仓鼠卵巢细胞多药耐药蛋白（P-糖蛋白，Pgp）的ATP酶活性。确定了Pgp在其天然质膜环境和纯化重组蛋白中的催化特性。一般来说，两种Pgp制剂表现相似，对MgATP亲和力低，核苷酸特异性低，偏好Mg-核苷酸，最适pH接近7.5。未发现参与催化的高亲和力结合位点。有效的共价灭活剂有NBD-C1、NEM、8-叠氮基ATP和2-叠氮基ATP。DCCD、FITC和磷酸吡哆醛只有微弱的抑制作用。发现脂质组成会影响纯化重组Pgp中药物对ATP酶的刺激程度，这表明脂质环境会影响药物结合位点与催化位点之间的偶联，并且在不同组织中表达的Pgp可能表现出不同的功能特性。
