Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Normal rat renal cortex contains three renal disease-inducing substances, that is, nephritogenoside, FX1A and immunogenoside (a novel renal glycoprotein that has the biological activity to induce only active Heymann nephritis). When renal cortex homogenate was treated with a detergent, Triton X-100, nephritogenoside was not eluted in the supernatant in which massive doses of FX1A and immunogenoside were detected. Thus, we searched for nephritogenoside in the precipitate. The precipitate was solubilized with trypsin, and nephritogenoside was easily and effectively isolated through columns of DEAE-cellulose followed by Bio-Gel A-1.5 m. The purified sample thus obtained is only composed of nephritogenoside, and contains neither FX1A nor immunogenoside. The yield of purified nephritogenoside was 3.8 mg (starting from 150 rats), which is about 5-6 times the recovery of the previous methodology. This newly developed simple method may be useful for the isolation of purified nephritogenoside. The chemical and immunologic properties of the purified sample prepared by the new method corresponded well with those of the nephritogenoside which was obtained by the previous methodology after exhaustive digestions with three proteolytic enzymes from homologous renal cortex.
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PMID:Nephritogenic glycoprotein. XIV. A simple isolation method of nephritogenoside. 236 28

Purified brush border fractions prepared from rat kidneys were solubilized in detergent, iodinated, and subjected to immunoprecipitation to identify the pathogenic antigen present in brush border membranes that is responsible for the production of Heymann nephritis (HN). Purified IgG prepared from the sera of rabbits or rats immunized with a crude cortical preparation, known as Fx1A, precipitated multiple peptides, whereas IgG eluted from glomeruli of rats with active or passive HN specifically immunoprecipitated a single large glycoprotein (Mr = 330,000). This protein (gp330) was subsequently purified by gel filtration and lentil lectin affinity chromatography from detergent-solubilized brush border membranes. When rats were immunized with purified gp330, they developed anti-brush border antibodies and active HN. IgG prepared from the serum of rats with active HN caused passive HN when injected into normal recipients. Rats immunized against brush border membrane proteins depleted of gp330 developed anti-brush border antibodies but did not develop HN. Further analysis of gp330 indicated that it is solubilized by detergent treatment of isolated brush border microvilli, and its antigenic component is released from intact microvilli by trypsin. By immunoperoxidase staining it was localized to the luminal side of the brush border membranes. These results indicate that (i) gp330 is the pathogenic antigen of HN; (ii) the antigen is a glycoprotein of the brush border membrane; and (iii) it is disposed with its pathogenic domain(s) facing the tubule lumen.
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PMID:The pathogenic antigen of Heymann nephritis is a membrane glycoprotein of the renal proximal tubule brush border. 675 52

Heymann nephritis developed in rats immunized with brush border membrane fractions isolated from rat kidney tubules. Glomerular autoantibodies eluted from cryostat sections of nephritic kidneys reacted in immunoelectron microscopy with the outer surface of isolated brush border membrane vesicles. This indicates that the autoantigens are plasma membrane components. To characterize further the chemical nature of the nephritogenic autoantigens, we treated the brush border membranes with trypsin and sodium deoxycholate, and the solubilized membranes were then fractionated by lectin affinity chromatography. The polypeptide composition of the fractions was analyzed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The capacity of the membrane fractions to induce Heymann nephritis was assessed by observing the development of typical renal lesions, antibrush border autoantibodies, and proteinuria in rats immunized with these fractions. The results suggest that the nephritogenic autoantigen is an integral component of the brush border membrane of kidney proximal tubules and has an affinity for Lens culinaris agglutinin. This indicates that it is a glycoprotein and has mannosyl and/or glycosyl groups exposed in its oligosaccharide side chains.
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PMID:Heymann nephritis induced by kidney brush border glycoproteins. 744 31