Abstract We successfully synthesized trifluoromethylated β-ketosulfones via the reaction of vinyl triflates with alkenes employing aqueous sulfurous acid as an external source of SO2. The PhSSPh/photoinitiated reaction with vinyl triflates that contain electron-deficient groups or halogens did not show any base-related effects, whereas the radical reaction was impeded in the absence of a base in the case of vinyl triflates generated from phenylacetylenes.
Precursor forms of lysosomal cathepsins B, H and L in the hepatic endoplasmic lumen were identified as having a molecular weight of 39-, 41-, and 39-kDa, respectively, by immunoblotting analysis. The proenzymes were then concentrated by applying the microsomal contents to a concanavalin A-Sepharose chromatography. The concanavalin A-adsorbed fractions containing the proenzymes showed no appreciable activities of cathepsins B, H and L. When those fractions were incubated at pH 3.0, the enzymatic activities markedly increased. Immunoblotting analysis showed that after 36 hr incubation the proenzymes disappeared and the mature enzymes increased. Thus the proenzymes were processed to the mature enzymes under acidic conditions of pH 3.0. The marked increased of enzymatic activities and the conversion of the proenzymes to the mature forms were completely blocked with pepstatin which is a potent inhibitor of aspartic proteinases. The results strongly suggested that a processing proteinase for procathepsins B, H, and L might be cathepsin D, a major lysosomal aspartic proteinase. Indeed, lysosomal cathepsin D could convert the immunoaffinitypurified microsomal procathepsin B to the mature enzyme in vitro. Therefore, procathepsins B, H, and L seem to be firstly synthesized as the enzymatically inactive forms in endoplasmic reticulum and may successively be converted into the active forms by cathepsin D in lysosomal compartments.
Journal Article Purification and Processing of Rat Liver Procathepsin B Get access Takahiro Kawabata, Takahiro Kawabata Division of Physiological Chemistry, Faculty of pharmacetutical Sciences, Kyusha University,Higashi-ku, Fukuoha 812 Search for other works by this author on: Oxford Academic PubMed Google Scholar Yukio Nishimura, Yukio Nishimura Division of Physiological Chemistry, Faculty of pharmacetutical Sciences, Kyusha University,Higashi-ku, Fukuoha 812 Search for other works by this author on: Oxford Academic PubMed Google Scholar Masahide Higaki, Masahide Higaki Division of Physiological Chemistry, Faculty of pharmacetutical Sciences, Kyusha University,Higashi-ku, Fukuoha 812 Search for other works by this author on: Oxford Academic PubMed Google Scholar Keitaro Kato Keitaro Kato 2 Division of Physiological Chemistry, Faculty of pharmacetutical Sciences, Kyusha University,Higashi-ku, Fukuoha 812 2To whom correspondence should be addresed. Search for other works by this author on: Oxford Academic PubMed Google Scholar The Journal of Biochemistry, Volume 113, Issue 3, March 1993, Pages 389–394, https://doi.org/10.1093/oxfordjournals.jbchem.a124056 Published: 01 March 1993 Article history Received: 04 November 1992 Published: 01 March 1993
We report a new methodology for the synthesis of γ-trifluoromethylated ketones from alkenes and vinyl triflate bifunctional reagents. The reaction proceeds via the addition of a β-trifluoromethyl alkyl radical to a vinyl triflate, followed by β-cleavage. We also demonstrate a one-pot version of the reaction for the vicinal functionalization of alkenes from alkynes.
Porcine edema disease (ED) is a life-threatening toxemia caused by enteric infection with Shiga toxin 2e (Stx2e)-producing Escherichia coli (STEC) in weaned piglets. We previously reported that the stx2eB-transgenic lettuce 2BH strain shows potential for use as an oral vaccine candidate against ED. However, the 2BH strain expressed a hemagglutinin (HA)-tag together with Stx2eB and contained non-canonical N-glycosylation. Therefore, we developed two Stx2eB-lettuce strains, the 3(G+) strain in which the HA-tag was removed from 2BH, and the 3(G–) lettuce strain, in which the 73rd Asn was replaced with Ser to prevent non-canonical N-glycosylation of Stx2eB from the 3(G+) strain. We examined the protective effect of these newly developed two strains compared with the previous 2BH strain against ED using a colostrum-deprived piglet STEC infection model. We found that the N-glycosylated 2BH and 3(G+) strains relieved the pathogenic symptoms of ED in STEC-challenged piglets, whereas the non-glycosylated 3(G–) strain did not. N-Glycosylation of the Stx2eB product in lettuce may be involved in the immune response in piglets.
