[Proteinases of small intestine enterocytes of swine. Purification and properties of aspartyl proteinase similar to cathepsin D].
A new aspartic proteinase was isolated from porcine intestine mucosa by affinity chromatography on pepstatin-Sepharose 4B and gel filtration on Sephadex G-100. The enzyme was purified 1600-fold and appeared homogeneous upon polyacrylamide gel electrophoresis. The proteinase has a Mr 60 000 +/- 4000 Da. During sodium dodecyl sulfate polyacrylamide gel electrophoresis the enzyme produced a single protein band (Mr 30 000 +/- 3000 Da). Isoelectric focusing revealed that the enzyme has several multiple forms (pI 6.9, 7.5, 8,0). The enzyme is a glycoprotein containing 5.9% of carbohydrates; the mannose to galactose ratio is 1:3. The amino acid composition of the enzyme was studied. The proteinase splits an oxidized insulin B-chain and synthetic substrates. The pH optimum is 3.2. The enzyme is immunologically identical to porcine spleen cathepsin D.
D000818:Animals; D016282:Aspartic Acid Endopeptidases; D002402:Cathepsin D / Q000032:analysis / Q000302:isolation & purification*; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000032:analysis / Q000302:isolation & purification*; D006868:Hydrolysis; D005779:Immunodiffusion; D007413:Intestinal Mucosa / Q000166:cytology / Q000201:enzymology*; D007421:Intestine, Small / Q000166:cytology / Q000201:enzymology*; D007525:Isoelectric Focusing; D008970:Molecular Weight; D013552:Swine
D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; D002402:Cathepsin D
Proteinazy énterotsitov tonkogo kishechnika svin'i. Ochistka i svoĭstva aspartil'noĭ proteinazy, skhodnoĭ s katepsinom D.