Title: Molecular Basis of Intracellular Regulation of Thiol Proteinase Inhibitors
Abstract: This chapter discusses presents the analysis of three major lysosomal thiol proteinases: cathepsin B, cathepsin H, and cathepsin L. Cathepsin B is characterized by its ability to hydrolyze Z-Ala-Arg-Arg-MCA. Cathepsin H has aminopeptidase but relatively little endopeptidase activity. Among thiol proteinase inhibitors, only the inhibitor from rat liver contains a cysteinyl residue near the amino-terminal portion. Lysosomal thiol proteinases are present in various tissues of mammals. Most intracellular thiol proteinases are localized in lysosomes. The target enzymes for intracellular thiol proteinase inhibitors are possibly lysosomal thiol proteinases. The epidermal type of inhibitor does not undergo regulation of activity by glutathione disulfide, as does the liver type of inhibitor. Several cytosolic enzymes are detected in autophagic vacuoles from the livers of leupeptin-treated rats. The cysteinyl residues at positions 3 and 64 of the rat liver thiol proteinase inhibitor are not essential for the formation of a complex with the thiol proteinase, because the carboxamido-methylated inhibitor still forms a complex with cathepsin H.
Publication Year: 1985
Publication Date: 1985-01-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 29
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