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Cells of the human promyelocytic HL60 line were induced to differentiate into granulocyte-like cells with dimethylsulphoxide (DMSO) or macrophage-like cells with 12-0-tetradecanoylphorbol-13-acetate (TPA). The synthesis of Cathepsin B by these cells was studied by immunoperoxidase staining and assay of cell lysates using the fluorimetric substrate benzoyloxycarbonyl-phenylanalyl-arginine-4-methyl-7-coumarylamide. Only 2–5% of the uninduced HL60 cells and DMSO-induced cells were immunohistochemically positive for Cathepsin B, compared with over 80% of the TPA-induced cells. Cathepsin B activity was lowest in the lysates of uninduced HL60s. DMSO-induced cells contained 1.5–2-fold the enzyme activity of HL60s and TPA-induced cell lysates demonstrated 5–14-fold the activity of uninduced HL60s. Induction of Cathepsin B synthesis was therefore associated with differentiation of the promyelocytes into cells of the monocyte/macrophage type, but not granulocyte-like cells. Cathepsin B was located immunohistochemically in human palatine tonsils. The enzyme was only demonstrated within macrophages in these tissues. Cathepsin B may therefore be a useful immunohistochemical marker for malignant and nonmalignant cells of the monocyte/macrophage lineage. 相似文献
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Sialoadhesin, a macrophage sialic acid binding receptor for haemopoietic cells with 17 immunoglobulin-like domains. 总被引:15,自引:0,他引:15 下载免费PDF全文
P R Crocker S Mucklow V Bouckson A McWilliam A C Willis S Gordon G Milon S Kelm P Bradfield 《The EMBO journal》1994,13(19):4490-4503
Sialoadhesin is a macrophage-restricted adhesion molecule of 185 kDa that mediates sialic acid-dependent binding to cells. It is expressed strongly by macrophages in lymphoid and haemopoietic tissues where it is likely to mediate cell-cell interactions. Here we report the molecular cloning of murine sialoadhesin and show that it is a new member of the immunoglobulin (Ig) superfamily with 17 Ig-like domains. COS cells transfected with a cDNA encoding full-length sialoadhesin bound mouse bone marrow cells in a sialic acid-dependent manner. Alternatively spliced cDNAs, predicting soluble forms of sialoadhesin containing the first three or 16 Ig-like domains of sialoadhesin, were expressed in COS cells and the respective proteins purified. When immobilized on plastic, the 16-domain form bound cells in a sialic acid-dependent manner, suggesting that sialoadhesin can function in both secreted and membrane-bound forms. The most similar proteins in the database were CD22, myelin-associated glycoprotein, Schwann cell myelin protein and CD33. Like sialoadhesin, CD22 mediates sialic acid-dependent cell adhesion. The sequence similarity of sialoadhesin to CD22 and related members of the Ig superfamily indicates the existence of a novel family of sialic acid binding proteins involved in cell-cell interactions. 相似文献
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M Platz A S Admasu S Kwiatkowski P J Crocker N Imai D S Watt 《Bioconjugate chemistry》1991,2(5):337-341
The photolysis of 3-(4-tolyl)-3-(trifluoromethyl)diazirine in the presence of benzene, methanol, carbon tetrachloride, cyclohexane, triethylsilane, or diethylamine led to photoproducts consistent with the intermediacy of a singlet carbene. In the case of diethylamine, the photoinsertion into the N-H bond of diethylamine produced the expected adduct, 1-(diethylamino)-2,2,2-trifluoro-1-(4-tolyl)ethane. However, the base-catalyzed elimination of hydrogen fluoride from this adduct afforded an enamine, alpha-(diethylamino)-beta,beta-difluoro-4-methylstyrene, and the subsequent hydrolysis of this enamine furnished diethylamine and 2,2-difluoro-1-(4-tolyl)ethanone. This elimination and hydrolysis sequence effectively reversed the photoinsertion process. A similar photoinsertion and hydrolysis process using 3-(4-n-octylphenyl)-3-(trifluoromethyl)diazirine also produced 2,2-difluoro-1-(4-n-octylphenyl)ethanone in modest yield. These results suggest that the photoinsertion products from 3-aryl-3-(trifluoromethyl)-diazirines in biological systems may suffer similar fates limiting, in part, their utility in obtaining primary sequence data. 相似文献
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