Myllylä R, Koivu J, Pihlajaniemi T, Kivirikko K I
Eur J Biochem. 1983 Jul 15;134(1):7-11. doi: 10.1111/j.1432-1033.1983.tb07523.x.
A high correlation was found between the activities of protein disulphide isomerase and prolyl 4-hydroxylase when assayed in cells synthesizing various collagen types or the same type at markedly different rates. The highest activities of both enzymes were found in freshly isolated chick-embryo tendon and cartilage cells, intermediate activities in confluent cultures of human skin and lung fibroblasts and mouse 3T6 fibroblasts, and the lowest values in three human sarcoma cell lines, the difference in protein disulphide isomerase activity between the freshly isolated tendon cells and confluent simian-virus-40-transformed human lung fibroblasts being about 25-fold. All these differences are in good agreement with differences reported between the various cells in their rates of collagen synthesis. A great similarity was also found between the changes in the two enzyme activities measured per cell during the growth of 3T6 fibroblast cultures from the early logarithmic phase to the stationary phase. No correlation was found between protein disulphide isomerase activity and the type of collagen synthesized. The data suggest that protein disulphide isomerase may be involved in the formation of intra-chain and inter-chain disulphide bonds in procollagens, but there is no collagen type-related variation in this enzyme activity of a magnitude that would explain the marked differences in the rates of formation of inter-chain disulphide bonds between the various collagen types.
在对合成各种类型胶原蛋白或以明显不同速率合成同一种类型胶原蛋白的细胞进行检测时，发现蛋白质二硫键异构酶和脯氨酰4-羟化酶的活性之间存在高度相关性。两种酶的最高活性见于刚分离的鸡胚肌腱和软骨细胞，中等活性见于人皮肤和肺成纤维细胞以及小鼠3T6成纤维细胞的汇合培养物，而在三种人肉瘤细胞系中的活性最低，刚分离的肌腱细胞与汇合的猿猴病毒40转化的人肺成纤维细胞之间的蛋白质二硫键异构酶活性差异约为25倍。所有这些差异与各种细胞在胶原蛋白合成速率方面报道的差异高度一致。在3T6成纤维细胞培养物从对数早期生长到稳定期的过程中，每个细胞所测的两种酶活性的变化之间也发现了很大的相似性。未发现蛋白质二硫键异构酶活性与合成的胶原蛋白类型之间存在相关性。数据表明，蛋白质二硫键异构酶可能参与前胶原蛋白中链内和链间二硫键的形成，但该酶活性不存在与胶原蛋白类型相关的变化，其幅度不足以解释各种胶原蛋白类型之间链间二硫键形成速率的显著差异。
