Open AccessBiosynthesis of glycoproteins in Candida albicans : Biochemical characterization of a soluble α‐mannosidase
Author(s) -
VázquezReyna Ana Bertha,
BalcázarOrozco Rosalía,
FloresCarreón Arturo
Publication year - 1993
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1993.tb05983.x
Subject(s) - tris , hydrolysis , chemistry , substrate (aquarium) , mannosidase , chromatography , candida albicans , protease , size exclusion chromatography , glycoprotein , swainsonine , enzyme , corpus albicans , molecular mass , biochemistry , biology , microbiology and biotechnology , ecology , yeast
Most α‐mannosidase activity (80%) in C. albicans was found in a soluble form. Addition of protease inhibitors to explore proteolytic release from a particulate cell component during enzyme preparation did not change this distribution. Molecular mass, calculated from gel filtration chromatography, was 417 kDa. Optimum pH was 6.0 with 50 mM Mes‐Tris when p‐nitrophenyl‐α‐ d ‐mannopyranoside was used as substrate. Optimum temperature was 42°C with either 10 mM phosphate buffer (pH 6.8) or 50 mM Mes‐Tris buffer (pH 6.0) and with 4‐methylumbelliferyl‐α‐ d ‐mannopyranoside as substrate. Apparent K m values for p‐nitrophenyl‐α‐ d ‐mannopyranoside and 4‐methylumbelliferyl‐α‐ d ‐mannopyranoside were 3.3 mM and 0.1 mM, respectively. 1 mM 1‐deoxymannojirimycin and 0.3 mM swainsonine inhibited the hydrolysis of 4‐methylumbelliferyl‐α‐ d ‐mannopyranoside by 67% and 83%, respectively, whereas that of p‐nitrophenyl‐α‐ d ‐mannopyranoside was only slightly diminished (10–15%).