Elmoselhi A B, Blennerhassett M, Samson S E, Grover A K
Department of Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.
Mol Cell Biochem. 1995 Oct 18;151(2):149-55. doi: 10.1007/BF01322337.
Pig coronary artery cultured smooth muscle cells were skinned using saponin. In the presence of an ATP-regenerating system and oxalate, the skinned cells showed an ATP-dependent azide insensitive Ca(2+)-uptake which increased linearly with time for > 1 h. The Ca(2+)-uptake occurred with Km values of 0.20 +/- 0.03 microM for Ca2+ and 400 +/- 34 microM for MgATP2-. Thapsigargin and cyclopiazonic acid inhibited this uptake with IC50 values of 0.13 +/- 0.02 and 0.56 +/- 0.04 microM, respectively. These properties of SR Ca(2+)-pump are similar to those reported for membrane fractions isolated from fresh smooth muscle of coronary artery and other arteries. However, optimum pH of the uptake in the skinned cells (6.2) was lower than that reported previously using isolated membranes (6.4-6.8).
使用皂角苷对猪冠状动脉培养的平滑肌细胞进行透膜处理。在存在ATP再生系统和草酸盐的情况下，透膜处理后的细胞表现出对叠氮化物不敏感的、依赖ATP的Ca(2+)摄取，这种摄取在超过1小时的时间内随时间呈线性增加。Ca(2+)摄取发生时，Ca2+的Km值为0.20±0.03微摩尔，MgATP2-的Km值为400±34微摩尔。毒胡萝卜素和环匹阿尼酸分别以0.13±0.02和0.56±0.04微摩尔的IC50值抑制这种摄取。肌浆网Ca(2+)泵的这些特性与从冠状动脉和其他动脉的新鲜平滑肌中分离出的膜部分所报道的特性相似。然而，透膜处理后的细胞摄取的最佳pH值（6.2）低于先前使用分离膜所报道的pH值（6.4 - 6.8）。
