Systematic search for novel proteinases in gastrointestinal tract and studies on their physiological roles and structure/function

1.从猪胃窦粘膜中分离到一种能特异性降解血管活性肠肽的膜结合丝氨酸蛋白酶和一种膜结合胞内胰蛋白酶，并对其进行了鉴定。2.从大鼠十二指肠cDNA文库中分离、克隆了肠肽酶cDNA，并对其一级结构进行了推测。此外，本发明还提供了一种方法，3.从猪脑中分离到一种新的膜相关金属蛋白酶，该酶能特异性降解前胃泌素肽，并对其进行了鉴定。5.从鳖胃粘膜中分离并鉴定了胃蛋白酶原的同工酶，7.胰蛋白酶和α-糜蛋白酶在高碱性pH（pH-13）条件下能选择性地切割Arg-X和Phe-X键; 8.与本课题有关的是，对一些其它蛋白酶进行了另外的表征研究，包括卵泡蛋白酶、脯氨酰内肽酶、酸性蛋白酶B和信号肽酶以及菠萝蛋白酶抑制剂。

1.A novel membrane-bound serine proteinase degrading vasoactive intestinal polypeptide fairly specifically and a novel membrane-associated intracellular trypsin were isolated from porcine gastric antral mucosa and characterized.2.Enteropeptidase cDNA was isolated and cloned from the cDNA library of rat duodenum and its primary structure was deduced. In addition, the tissue distributionof its mRNA was analyzed.3.A novel membrane-associated metalloproteinase degrading progastrin peptide fairly specifically was isolated from porcine brain and characterized.4.The microsomal membrane-bound serine proteinase from rat liver was identified as hepsin from analyzes of its polypeptide chain composition and partialamino acid sequence.5.Pepsinogen isoforms were isolated and characterized from the gastric mucosae of turtle and tuna stomach and the amino acid sequences of their major forms were determined.6.Normal human blood alpha _2-macroglobulin was shown to contain a small but significant amount of novel serine proteinase (s) naturally entrapped in it.7.Pancreatic trypsin and alpha-chymotrypsin were shown to selectively cleave Arg-X and Phe-X bonds, respectively, at a high alkaline pH (pH-13).8.In relation to this project, additional characterization studies were performed on some other proteinases including follipsin, prolylendopeptidase, acid proteinase B,and signal peptidase and bromelain inhibitors.