Microstructure of Sialoglycoprotein Obtained From Hen' s Egg White And Its Biological Activities.

本研究从鸡蛋白色中制备了唾液酸糖蛋白（卵粘蛋白、卵类粘蛋白、卵黄素蛋白和卵糖蛋白），并测定了它们的生物学活性（抗SR-180和MH 134细胞的活性，以及对轮状病毒和纽卡斯尔疫病毒血凝的抑制活性）。卵粘蛋白是唾液酸糖蛋白中活性最高的一种。从超声处理的卵粘蛋白中分离α-卵粘蛋白（颗粒重量约180，000）和β-卵粘蛋白（颗粒重量约400，000），并测定它们的活性。发现β-卵粘蛋白显示出比α-卵粘蛋白更高的活性。从链霉蛋白酶消化的卵粘蛋白和β-卵粘蛋白中，通过离子交换和凝胶过滤柱色谱分离它们的片段。并比较了各片段的生物活性与化学组成的关系。结果表明，β-卵粘蛋白由两个富含碳水化合物的部分和三个缺乏碳水化合物的部分组成，其中富含碳水化合物的部分含有O-连接的碳水化合物链（分子量约为120，000），而缺乏碳水化合物的部分含有N-连接的碳水化合物链（分子量约为50，000）。前者主要涉及生物学活动。通常，卵粘蛋白的生物活性被证明是通过含有与肽链连接的唾液酸的碳水化合物链的作用来呈现的，如在β-卵粘蛋白中富含碳水化合物的部分中所见。

In this study, sialoglycoproteins (ovomucin, ovomucoid, ovoflavoprotein and ovoglycoprotein) were prepared from hen' s egg white and their biological activities (antitumor activities against SR-180 and MH134 cell, and inhibitory activities of hemagglutination by rotavirus and newcastle disease virus) were determined. Ovomucin was found to have the specific higher activities among the used sialoglycoproteins. alpha-Ovomucin (particle weight about 180,000) and beta-ovomucin (particle weight about 400,000) were fractionated form sonicated ovomucin and their activities were also determined. beta-Ovomucin was found to show higher activities than alpha-ovomucin. From the pronase-digested ovomucin and beta-ovomucin, their fragments were separated by ion-exchange and gel-filtration column chromatographies. And the relationship between biological activities and chemical composition of each fragment was compared. It was demonstrated that beta-ovomucin was comprised of two carbohydrate-rich parts containing 0-linked carbohydrate chain (molecular weight about 120,000) and three carbohydrate-poor parts containing N-linked carbohydrate chain (moleular weight about 50,000) . And the former was mainly concerned in the biological activities. In generally, biological activities of ovomucin were demonstrated to present by the action of carbohydrate chain containing sialic acid linked with peptide chain, as seen in carbohydrate-rich parts in beta-ovomucin.