Levitsky D O, Benevolensky D S, Ikemoto N, Syrbu S I, Watras J
Institute of Experimental Cardiology, Academy of Medical Sciences, Moscow, USSR.
J Mol Cell Cardiol. 1989 Feb;21 Suppl 1:55-8. doi: 10.1016/0022-2828(89)90837-7.
A monoclonal antibody (mAb 4B4) was raised against purified sarcoplasmic reticulum vesicles from canine myocardium, and shown to inhibit Ca2+ uptake by microsomes isolated from cardiac, skeletal, and smooth muscle. The amount of mAb 4B4 needed to inhibit the Ca2+ uptake 50% at a given membrane concentration correlated with the amount of Ca2+ pump protein in the microsomal preparation. This is consistent with the observation the mAb 4B4 binds specifically to the sarcoplasmic/endoplasmic reticulum Ca2+ pump (Mr 100 kDa), but has no effect on the T-tubule Mg2+-ATPase. Changes in the binding of mAb 4B4 to crude microsomes isolated from dog heart after various durations of global ischemia showed that the decrease in microsomal Ca2+ transport during the first 15 min of ischemia correlated with a loss of active Ca2+ pump molecules. The monoclonal antibody mAb 4B4 may therefore serve as a specific marker for the sarcoplasmic/endoplasmic reticulum Ca2+ pump system in various cells, and can provide quantitative information about the loss of active Ca2+ pump proteins under pathological conditions.
制备了一种针对犬心肌纯化肌浆网囊泡的单克隆抗体（mAb 4B4），该抗体可抑制从心脏、骨骼肌和平滑肌分离的微粒体对Ca2+的摄取。在给定膜浓度下，抑制Ca2+摄取50%所需的mAb 4B4量与微粒体制剂中Ca2+泵蛋白的量相关。这与mAb 4B4特异性结合肌浆网/内质网Ca2+泵（分子量100 kDa）但对横管Mg2+-ATP酶无影响的观察结果一致。在不同时长的全心缺血后，mAb 4B4与从犬心脏分离的粗微粒体结合的变化表明，缺血最初15分钟内微粒体Ca2+转运的减少与活性Ca2+泵分子的丢失相关。因此，单克隆抗体mAb 4B4可作为各种细胞中肌浆网/内质网Ca2+泵系统的特异性标记物，并能提供病理条件下活性Ca2+泵蛋白丢失的定量信息。
