Open AccessIsoelectric Focusing Studies on the -Fructofuranosidases and -Glucosidases of Streptococcus mitis
Author(s) -
MarieLouise Sund,
Lars Linder,
Carita Andersson
Publication year - 1978
Publication title -
journal of general microbiology/journal of general microbiology
Language(s) - English
Resource type - Journals
eISSN - 2059-9323
pISSN - 0022-1287
DOI - 10.1099/00221287-106-2-337
Subject(s) - maltose , raffinose , isoelectric focusing , sucrose , incubation , fructose , isoelectric point , chemistry , trehalose , biochemistry , chromatography , streptococcus mitis , isomaltose , hydrolysis , enzyme , biology , bacteria , streptococcus , genetics
Extracts of Streptococcus mitis ATCC 903 were analysed for beta-fructofuranosidase and alpha-glucosidase activities by isoelectric focusing in thin-layer polyacrylamide gels combined with zymogram procedures. Three bands of activity were visualized in the gels after incubation with sucrose (pI 4.05, 4.25 and 4.85) and three other bands after incubation with p-nitrophenyl alpha-D-glucopyranoside (pI 3.90, 4.45 and 4.65). The enzymes responsible for the reaction with sucrose were identified as beta-fructofuranosidases (EC 3.2.1.26) for the following reasons: identical enzyme bands were visualized in the gels after incubation with raffinose; no enzyme bands appeared in the gel after incubation with the alpha-glucosides maltose, turanose, trehalose and melezitose; and the soluble fraction hydrolysed sucrose to equimolar amounts of glucose and fructose.