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Two classes of modern missing data procedures, maximum likelihood (ML) and multiple imputation (MI), tend to yield similar results when implemented in comparable ways. In either approach, it is possible to include auxiliary variables solely for the purpose of improving the missing data procedure. A simulation was presented to assess the potential costs and(More)
We have purified a 30-kDa serine protease (designated RNK-Met-1) from the granules of the rat large granular lymphocyte leukemia cell line (RNK-16) that hydrolytically cleaves model peptide substrates after methionine, leucine, and norleucine (Met-ase activity). Utilizing molecular sieve chromatography, heparin-agarose, chromatography, and reverse-phase(More)
Natural killer (NK) and cytotoxic T-lymphocytes (CTLs) kill cells within an organism to defend it against viral infections and the growth of tumors. One mechanism of killing involves exocytosis of lymphocyte granules which causes pores to form in the membranes of the attacked cells, fragments nuclear DNA and leads to cell death. The cytotoxic granules(More)
The release of cytotoxic granule contents by cytotoxic T lymphocytes triggers apoptotic target cell death. Cytotoxic granules contain a pore-forming protein, perforin, and a group of serine proteases called granzymes. We expressed human granzyme A in bacteria as a proenzyme capable of in vitro activation by enterokinase. The recombinant activated enzyme has(More)
Inhibition of complement proteins D, B, C2, C1s, C1r, I, and the catalytic fragments Bb and C2a by substituted isocoumarins was investigated. 3,4-Dichloroisocoumarin, a general serine protease inhibitor, inhibited factor D, C1r, and C1s moderately with second-order inhibition constants (kobs/[I]) of 40 to 190 M-1 s-1, but it did not inhibit C2, factor B,(More)
We recently reported the purification of a lymphocyte granule protein called "fragmentin," which was identified as a serine protease with the ability to induce oligonucleosomal DNA fragmentation and apoptosis (Shi, L., R. P. Kraut, R. Aebersold, and A. H. Greenberg. 1992. J. Exp. Med. 175:553). We have now purified two additional proteases with fragmentin(More)
To kill other cells, lymphocytes can exocytose granules that contain serine proteases and pore-forming proteins (perforins). We report that mechanism-based isocoumarin inhibitors inhibited the proteases and inactivated lysis. When inhibited proteases were restored, lysis was also restored, indicating that the proteases were essential for lysis. We found(More)
Serine proteases (granzymes) contained within the cytoplasmic granules of cytotoxic T cells and natural killer cells play a variety of roles including the induction of target cell apoptosis, breakdown of extracellular matrix proteins and induction of cytokine secretion by bystander leukocytes. Different granzymes display proteolytic specificities that mimic(More)
The broadly reactive cysteine protease dipeptidyl peptidase I (DPPI, cathepsin C) is thought to activate all progranzymes (zymogens of lymphocyte serine proteases) to form mature granzymes. We synthesized dipeptide 7-amino-4-methylcoumarin (AMC) substrates containing progranzyme activation sequences and showed that they were efficiently hydrolyzed by DPPI.(More)
Granzyme B (GranB), a serine protease stored in the granules of cytotoxic T lymphocytes and natural killer cells, can initiate target cell apoptosis. To produce large amounts of purified active enzyme, recombinant murine granzyme B (rGranB) was expressed from baculovirus in insect cells. The expressed rGranB is secreted into the culture medium and can be(More)