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Purification and Specificity of Two α‐Glucosidase Isoforms of the ParasiticProtist Trichomonas vaginalis
Author(s) -
KUILE BENNO H.,
HRDÝ IVAN,
SÁNCHEZ LIDYA B.,
MÜLLER MIKLÓS
Publication year - 2000
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.2000.tb00072.x
Subject(s) - gene isoform , maltose , biology , biochemistry , trichomonas vaginalis , alpha glucosidase , hydrolysis , isozyme , enzyme , microbiology and biotechnology , gene
. Two isoforms of α‐glucosidase were purified from the parasitic protist Trichomonas vaginalia. Both consisted of 103 kDa subunits, but differed in pH optimum and substrate specificity. Isoform 1 had a pH optimum around 4.5 and negligible activity on glucose oligomcrs other than maltose, while isoform 2 with a pH optimum of 5.5 hydrolyzed also such substrates at considerable rates. Neither had activity on glycogen or starch. Isoform 1 had a specific activity for hydrolysis of maltose of 30 U/mg protein and isoform 2 101 U/mg protein. The Km values were 0.4 mM and 2.0 mM, respectively. Isoform 2 probably corresponds to the activity detected on the cell surface.