AN ELASTIC PROTEIN IN CELL OF AORTA SMOOTH MUSCLE

众所周知，高分子量弹性蛋白（连接蛋白：3，000kDa）存在于横纹肌中，但不存在于平滑肌中。用0.1M磷酸钠缓冲液（pH6.6）从牛或鸡的主动脉肌中提取900 kDa的蛋白质。提取物用35mM磷酸钾缓冲液（pH7.0）透析后，用DEAE柱色谱法通过从35至60mM磷酸盐缓冲液梯度洗脱部分纯化蛋白质。纯化的蛋白质从鸡的砂囊交叉反应的多克隆抗体的900 kDa的蛋白质。抗体与鸡主动脉和肌胃总SDS抽提物中的900 kDa条带反应，经旋转阴影后在电镜下观察纯化蛋白。900 kDa蛋白质分子形状长且非常柔韧，类似于脊椎动物的横纹弹性蛋白（connectn），目前正在进行cDNA测序工作。

It is well known that a high melecular weight elastic protein, (connectin : 3,000 kDa) is present in striated muscle, but not in smooth muscle. However, a 900 kDa protein was detected by 2-6% SDS gel electrophoresis in smooth muscle.The 900 kDa protein was extracted from aorta of bovine or chicken gizzard smooth muscle, with 0.1 M sodium phosphate buffer (pH 6.6). After the extract was dialyzed against 35 mM potassium phosphate buffer (pH 7.0), the protein was partially purified with DEAE column chromatography by gradient elution from 35 to 60 mM phosphate buffer. The purified protein from chicken gizzard crossreacted with the plolyclonal antibodies to the 900 kDa protein. The antibodies reacted with the 900 kDa band in the total SDS extract of both chicken aorta and gizzard smooth muscle.The purified protein was observed under an electron microscope after rotary shadowing. The molecular shape of 900 kDa protein was long and very flexible, similar to vertebrate striated elastic protein (connectn).Now cDNA sequence work is under way.