title: Electrophoretic mobility of external invertase from free and gel-immobilized yeast cells.
abstract: Electrophoretic mobility of secreted invertase (E.C. 3.2.1.26) from gelatin-immobilized yeast cells was analysed and compared with that of secreted invertase from freely suspended batch-grown cells. Invertase from immobilized cells showed a lower mobility after 24 h of incubation, in medium containing either glucose or raffinose as carbon source. Changes in invertase mobility were also followed in a time course both for immobilized and for freely suspended batch-grown cells. Mobility of invertase from free cells increased after approximately 15 h of incubation, independently of the carbon source, whilst that of invertase from immobilized cells remained constant. The differences observed were attributed to a different level of glycosylation of the protein moiety in free and immobilized cells. The amount of mannoproteins in the cell walls of immobilized cells was also investigated by ConA-ferritin labelling and quantification of ferritin particle density in ultrathin sections; the results of this experiment showed a higher content of mannoproteins in the walls of immobilized cells when compared with free cells. As a whole, these results are indicative of physiological changes that can be ascribed to the peculiar microenvironment of gel-immobilized cells.
authors.affiliation: Dip. to Fisiologia Generale, Università degli Studi di Napoli, Italy.
authors.forename: E
authors.initials: E
authors.lastname: de Alteriis
authors.forename: J
authors.initials: J
authors.lastname: Zueco
authors.forename: H
authors.initials: H
authors.lastname: Rico
authors.forename: R
authors.initials: R
authors.lastname: Sentandreu
authors.forename: P
authors.initials: P
authors.lastname: Parascandola
mesh_terms: D015153:Blotting, Western; D017358:Cell Wall Skeleton / Q000648:ultrastructure; D006026:Glycoside Hydrolases / Q000737:chemistry*; D006031:Glycosylation; D066298:In Vitro Techniques; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008854:Microscopy, Electron; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D043324:beta-Fructofuranosidase
chemical_list: D017358:Cell Wall Skeleton; D008562:Membrane Glycoproteins; C025363:mannoproteins; D006026:Glycoside Hydrolases; D043324:beta-Fructofuranosidase