Studies on fibronectin-like protein of Japanese flounder

应用明胶酶谱技术在牙鲆肌肉、皮肤和血清中检测到新的明胶溶解活性。这一结果表明，这些活性可能是由于不同的酶。其中一种活性来自纤维连接蛋白样蛋白，其分子大小为200 kDa，对蛋白水解性敏感，组织分布广泛，对明胶和肝素有亲和力。纯化的蛋白可与抗鸡纤维连接蛋白抗体发生免疫交叉反应，并能在原代培养的牙鲆胚胎细胞和EPC细胞上有细胞铺展活性。在多种鱼类组织中均有表达。根据抑制作用，确定了丝氨酸酶(70k-120k)和金属酶(-lt；100k)。在大鼠组织中也有类似的活性，但活性明显弱于鱼类，这表明胶原蛋白在鱼类组织中的代谢速度高于哺乳动物组织。

Novel gelatinoltic activities were detected in Japanese flounder muscle, skin and serum by using gelatin-zymography. This result suggested the activities were possibly due to distinct enzymes. One of the activities were supposed to be derived from fibronectin-like protein based on the molecular weifht (>200kDa), sensitivity against proteolysis, wide tissue distribution, and affinity to gelatin and heparin.Fibronectin-like protein was purified by gelatin-affinity chromatography from Japanese flounder serum, which showed the gelatinolytic activity. The purified protein showed the immunological cross-reactivity with anti-chicken fibronectin antibody and the cell-spreading activity on the primary culture cells derived from Japanese flounder embryo and EPC cells.Other glatinolytic proteinases were demonstrated in various fish tissues. By the inhibitor effect, serine-type enzymes (70k-120k) and metallo-type enzyme (<100k) were identified. Similar activities were demonstrated in rat tissues, but the activities were remarkably weak compared with those of fishes, suggesting that the collagen would be metabolized at higher rate in fish tissues than in mammal tisuues.