Enghild J J, Thøgersen I B, Pizzo S V, Salvesen G
Pathology Department, Duke University Medical Center, Durham, North Carolina 27710.
J Biol Chem. 1989 Sep 25;264(27):15975-81.
The polypeptide chain composition of protein material referred to in the literature as "inter-alpha-trypsin inhibitor" was investigated. The material was found to consist of distinct proteins of 125,000 and 225,000 Da, each of which contained more than one polypeptide chain. The links that assemble each protein were found to be stable to various strong denaturants, but susceptible to treatment with trifluoromethanesulfonic acid or hyaluronidase, indicating a glycan nature. The 225,000-Da protein migrated with inter-alpha mobility on agarose gel electrophoresis and is designated inter-alpha-trypsin inhibitor, whereas the 125,000-Da protein migrated with pre-alpha mobility, and we designate it pre-alpha-trypsin inhibitor. Analysis of the proteins, the separated chains, and proteolytic derivatives thereof revealed that each protein contained a single, identical, trypsin-inhibitory chain of 30,000 Da. Inter-alpha-trypsin inhibitor contains noninhibitory heavy chains of 65,000 and 70,000 Da, whereas pre-alpha-trypsin inhibitor contains a heavy chain of 90,000 Da. Our data allow identification of several recently reported cDNA clones and clarify the confusion surrounding the composition of plasma proteins referred to as inter-alpha-trypsin inhibitor.
对文献中称为“α-间胰蛋白酶抑制剂”的蛋白质材料的多肽链组成进行了研究。发现该材料由分子量分别为125,000和225,000道尔顿的不同蛋白质组成，每种蛋白质都包含不止一条多肽链。发现组装每种蛋白质的连接对各种强变性剂稳定，但易受三氟甲磺酸或透明质酸酶处理的影响，表明具有聚糖性质。分子量为225,000道尔顿的蛋白质在琼脂糖凝胶电泳中以α-间移动性迁移，被指定为α-间胰蛋白酶抑制剂，而分子量为125,000道尔顿的蛋白质以前α移动性迁移，我们将其指定为前α-胰蛋白酶抑制剂。对这些蛋白质、分离的链及其蛋白水解衍生物的分析表明，每种蛋白质都包含一条分子量为30,000道尔顿的单一、相同的胰蛋白酶抑制链。α-间胰蛋白酶抑制剂包含分子量为65,000和70,000道尔顿的非抑制性重链，而前α-胰蛋白酶抑制剂包含一条分子量为90,000道尔顿的重链。我们的数据有助于鉴定几个最近报道的cDNA克隆，并澄清围绕称为α-间胰蛋白酶抑制剂的血浆蛋白组成的混乱情况。
