Poliovirus interactions with host cells were investigated by studying the formation of ribonucleoprotein complexes at the 3' end of poliovirus negative-strand RNA which are presumed to be involved in viral RNA synthesis. It was previously shown that two host cell proteins with molecular masses of 36 and 38 kDa bind to the 3' end of viral negative-strand RNA at approximately 3 to 4 h after infec...

Proteinase 3 is present in high concentration in the primary granules of acute and chronic myeloid leukemia blasts, and may represent a potential T-cell target antigen. We screened proteinase 3 against the binding motif of HLA-A2.1. Based on its high predicted binding, a 9-mer peptide, "PR-1," was synthesized and tested for binding to HLA-A2.1 using the T2 cell line. PR-1 at 100 micrograms/mL s...

The hydrolysis of (14)C-labeled ribulose-1,5-bisphosphate carboxylase (RuBPCase) by two partially purified endoproteinases from senescing barley (Hordeum vulgare v. Numar) leaves is described. The major thiol proteinase, EP(1), exhibits biphasic kinetics which appear to be caused by a region of the large subunit of RuBPCase that is highly sensitive to attack by EP(1). This proteinase further hy...

PURPOSE The purpose was to characterize the properties of a proteinase activity associated with betaA3-crystallin, which was isolated from the alpha-crystallin fraction of human lenses. METHODS An inactive, Arg-bond hydrolyzing proteinase in the alpha-crystallin fraction, which was isolated from the water soluble (WS) protein fraction of 60- to 70-year-old human lenses, was activated by sodiu...

2-fold. Lack of the vacuolar endoproteinases yscA and yscB reduces the protein degradation rate by about 30% under the conditions of canavanine-induced synthesis of false proteins (Table 2). The remaining protein degradation rate of 15% under starvation conditions, and of 6(r-70°h under growing conditions in mineral medium in strains defective in the two vacuolar endoproteinases yscA and yscB, ...

The effects of the Ca2+-activated cysteine proteinase, the rat trypsin-like serine proteinase and bovine trypsin on myofibrillar proteins from rabbit skeletal muscle are compared. 2. Myofibrils that had been treated at neutral pH with the Ca2+-dependent proteinase and with the rat enzyme were (a) analyzed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and (b) examined in the elec...

Four Ca2+-dependent proteinase activities in lobster claw and abdominal muscle have been resolved by high-performance liquid chromatography on gel filtration and ion-exchange columns. These activities, which do not appear to be generated by autolytic or other degradative processes, differed from each other in molecular weight (peak I, Mr = 310,000; peak IIa, Mr = 125,000; peak IIb, Mr = 195,000...

To determine the location of the proteinase in the covalent serpin-proteinase complex we prepared seven single-cysteine-containing variants of the Pittsburgh variant of the serpin a1-proteinase inhibitor, and we labeled each cysteine with the dansyl f luorophore. The dansyl probes were used to determine proximity of the proteinase trypsin in covalent and noncovalent complexes with the serpin, b...

Proteinase A and proteinase B, two vacuolar enzymes in Saccharomyces cerevisiae, are synthesized as larger precursors with apparent molecular weights of approximately 52,000 and 42,000, respectively. These precursor molecules are processed to their mature forms of 42,000 molecular weight for proteinase A and 33,000 molecular weight for proteinase B. In the presence of tunicamycin, an inhibitor ...

Human pulmonary alveolar macrophages obtained by bronchoalveolar lavage from both normal controls and smokers secreted in vitro a neutral proteinase that degraded denatured collagens. Optimal expression of the proteinase was detected after 3-5 d of culture. The proteinase could not be detected in the media of cultures that had been treated with 0.5 gg/ml of cycloheximide. The gelatinase had an ...