Title: | In vitro studies on the subcellular location of glucosidase I and glucosidase II in dog pancreas |
Author(s): | Bause E; Gunther R; Schweden J; Tillmann U; |
ISSN/ISBN: | 0144-8463 (Print) 0144-8463 (Linking) |
Abstract: | "When programmed with yeast prepro-alpha-factor mRNA, the heterologous reticulocyte/dog pancreas translation system synthesizes two pheromone related polypeptides, a cytosolically located primary translation product (pp-alpha-Fcyt, 21 kDa) and a membrane-specific and multiply glycosylated alpha-factor precursor (pp-alpha-F3, 27.5 kDa). Glycosylation of the membrane specific pp-alpha-F3 species is competitively inhibited by synthetic peptides containing the consensus sequence Asn-Xaa-Thr as indicated by a shift of its molecular mass from 27.5 kDa to about 19.5 kDa (pp-alpha-F0), whereas the primary translation product pp-alpha-Fcyt is not affected. Likewise, only the glycosylated pp-alpha-F3 structure is digested by Endo H yielding a polypeptide with a molecular mass between pp-alpha-F0 and pp-alpha-Fcyt. These observations strongly suggest that the primary translation product is proteolytically processed during/on its translocation into the lumen of the microsomal vesicles. We believe that this proteolytic processing is due to the cleavage of a signal sequence from the pp-alpha-Fcyt species, although this interpretation contradicts previous data from other groups. The distinct effect exerted by various glycosidase inhibitors (e.g. 1-deoxynojirimycin, N-methyl-dNM, 1-deoxymannojirimycin) on the electrophoretic mobility of the pp-alpha-F3 polypeptide indicates that its oligosaccharide chains are processed to presumably Man9-GlcNAc2 structures under the in vitro conditions of translation. This oligosaccharide processing is most likely to involve the action of glucosidase I and glucosidase II as follows from the specificity of the glycosidase inhibitors applied and the differences of the molecular mass observed in their presence.(ABSTRACT TRUNCATED AT 250 WORDS)" |
Keywords: | "Animals Dogs Endoplasmic Reticulum/metabolism Fungal Proteins/metabolism Glycoside Hydrolase Inhibitors Glycosylation Mating Factor Pancreas/*enzymology Peptides/metabolism Protein Biosynthesis *Protein Processing, Post-Translational Saccharomyces cerevis;" |
Notes: | "MedlineBause, E Gunther, R Schweden, J Tillmann, U eng Research Support, Non-U.S. Gov't England 1986/09/01 Biosci Rep. 1986 Sep; 6(9):827-34. doi: 10.1007/BF01117106" |