Keiser H D, Hatcher V B
Connect Tissue Res. 1977;5(3):147-55. doi: 10.3109/03008207709152265.
The basic subunit of cartilage proteoglycan consists of multiple glycosaminoglycan chains covalently attached to a core protein. It is unclear as to whether there is a single core protein or multiple different core proteins, since previous studies using either chondroitinase or testicular hyaluronidase to enzymatically remove chondroitin sulfate side chains from the proteoglycan subunit have yielded conflicting results. In the present study, a chondroitinase-produced core protein preparation isolated as a single peak on Sepharose gel chromatography was found to contain at least two immunologically distinct components. Hyaluronidase-produced core protein from the same proteoglycan subunit fraction was found to contain multiple components nearly all of which were smaller than the components in the chondroitinase digest. A possible explanation of these findings is that they resulted from proteolytic degradation of the core protein in the course of the enzymatic removal of its chondroitin sulfate. The presence of small amounts of protease contaminants in several commercial chondroitinase and hyaluronidase preparations was detected by an extremely sensitive radioassay. Until proteases can be rigorously excluded from enzyme preparations used to degrade the proteoglycan subunit, it will not be possible to determine whether it consists of a single or several different core proteins.
软骨蛋白聚糖的基本亚基由多条共价连接到核心蛋白的糖胺聚糖链组成。目前尚不清楚是否存在单一的核心蛋白或多种不同的核心蛋白，因为之前使用软骨素酶或睾丸透明质酸酶从蛋白聚糖亚基上酶解去除硫酸软骨素侧链的研究得出了相互矛盾的结果。在本研究中，在琼脂糖凝胶色谱上分离为单一峰的软骨素酶产生的核心蛋白制剂被发现至少含有两种免疫上不同的成分。从同一蛋白聚糖亚基部分获得的透明质酸酶产生的核心蛋白被发现含有多种成分，几乎所有成分都比软骨素酶消化产物中的成分小。对这些发现的一种可能解释是，它们是由于在酶解去除其硫酸软骨素的过程中核心蛋白发生了蛋白水解降解。通过一种极其灵敏的放射测定法检测到几种市售软骨素酶和透明质酸酶制剂中存在少量蛋白酶污染物。在用于降解蛋白聚糖亚基的酶制剂中能够严格排除蛋白酶之前，将无法确定它是由单一的还是几种不同的核心蛋白组成。
