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An alanyl-alanyl-phenylalanyl-7-amino-4-methylcoumarin-hydrolyzing protease particle copurifying with 26S proteasomes was isolated and identified as tripeptidyl peptidase II (TPPII), a cytosolic subtilisin-like peptidase of unknown function. The particle is larger than the 26S proteasome and has a rod-shaped, dynamic supramolecular structure. TPPII exhibits(More)
To generate peptides for presentation by major histocompatibility complex (MHC) class I molecules to T lymphocytes, the immune system of vertebrates has recruited the proteasomes, phylogenetically ancient multicatalytic high molecular weight endoproteases. We have previously shown that many of the proteolytic fragments generated by vertebrate proteasomes(More)
We have studied polypeptide processing by purified proteasomes, with regard to proteolytic specificity and cytotoxic T-lymphocyte (CTL) epitope generation. Owing to defined preferences with respect to cleavage sites and fragment length, proteasomes degrade polypeptide substrates into cohorts of overlapping oligopeptides. Many of the proteolytic fragments(More)
Mallory bodies (MBs) were obtained in purified form from human liver obtained at autopsy using a new procedure consisting of sedimentation through a Ficoll viscosity barrier. Preparations from six livers ranged in purity from 95 to 99 per cent. MB preparations were autofluorescent. MBs were strongly agglutinated by Concanavalin A. The presence of(More)
Horseradish peroxidase (HRP), a glycoprotein enzyme, bound specifically to Mallory bodies (MBs) in cryostat sections of autopsy liver and liver biopsies. In contrast, HRP did not bind to cryostat sections of normal liver. The specificity of HRP binding was also observed using light and electron microscopy in autopsy liver-derived subcell fractions prepared(More)
Cells lacking thymidine kinase (tk) have been reported to fail to respond to the action of interferon (IFN). While some laboratories have confirmed this observation, others have failed to do so. We studied the effect of IFN on four freshly isolated tk- lines of mouse L cells infected with mengovirus. In all cases, normal antiviral activity was induced. The(More)
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