title: The inhibition of the mitogenic stimulation of B lymphocytes by a serine protease inhibitor: commitment to proliferation correlates with an enhanced expression of a cell-associated arginine-specific serine enzyme.
abstract: By the use of diisopropylfluorophosphate (DFP) we have been able to show that the mitogenic stimulation of murine B lymphocytes can be maximally inhibited a few hours before commitment of the cells to DNA synthesis. This inhibition was shown to be specific for a serine enzyme(s). The results of experiments designed to determine the location of this enzyme indicated that the mitogens-linked serine enzyme is not a secreted extracellular factor but is cell-associated. Fluorographic analysis of electrophoretic gels of cell homogenates labeled with [3H]DFP revealed the presence of one major and three minor bands which were arginine-specific serine enzymes. In stimulated cells, there was a clear quantitative difference in the amount of [3H]DFP bound to the major band (approx. 23,000 m.w.) suggesting that this protein may be critical to the progression of the cells through the cell cycle into the S phase of DNA synthesis.
mesh_terms: D000818:Animals; D001120:Arginine / Q000378:metabolism; D001402:B-Lymphocytes / Q000201:enzymology / Q000276:immunology*; D004247:DNA / Q000096:biosynthesis; D010450:Endopeptidases / Q000378:metabolism; D005260:Female; D007531:Isoflurophate / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects*; D051379:Mice; D008808:Mice, Inbred CBA; D010960:Plasminogen Activators / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology*; D012697:Serine Endopeptidases; D013379:Substrate Specificity; D014106:Tosylarginine Methyl Ester / Q000494:pharmacology; D014373:Tuberculin / Q000276:immunology
chemical_list: D011480:Protease Inhibitors; D014373:Tuberculin; D007531:Isoflurophate; D004247:DNA; D014106:Tosylarginine Methyl Ester; D001120:Arginine; D010450:Endopeptidases; D010960:Plasminogen Activators; D012697:Serine Endopeptidases