Open AccessComparison of Penicillium amagasakiense glucose oxidase purified as glyco‐ and aglyco‐proteins
Author(s) -
Kim Jong Min,
Schmid Rolf D.
Publication year - 1991
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.1574-6968.1991.tb04446.x
Subject(s) - glucose oxidase , penicillium , biochemistry , chemistry , microbiology and biotechnology , enzyme , biology , food science
Summary Penicillium amagasakiense secreted glucose oxidase (GOD) with a highly diminished carbohydrate moiety (aglyco‐GOD) in the presence of 20 mg/l tunicamycin. To examine enzymatic properties of aglyco‐GOD, this and native GOD (glyco‐GOD) were purified to homogeneity from the culture medium with or without tunicamycin. The carbohydrate content of aglyco‐GOD was 2.9% and the M r of it and its subunit were 130 000 and 70 000, respectively. On the other hand, those from glyco‐GOD were 20.4%, 150 000 and 80 000, respectively. Nonetheless, they showed remarkably similar catalytic properties to each other: K m values of 3.4 and 2.7 mM and V max values of 320 and 270 U/mg protein. pH optima 5.5 and 6.0 were observed for aglyco and glyco‐GOD, respectively. Isoelectric focusing showed a strikingly similar pattern with each GOD having one major band of p I 4.2 and 2 minor bands between p I 4.3 and 4.5, which implies that microheterogeneity of GOD was not due to heterogeneous glycosylation. Up to 35°C, both enzyme preparations were stable for 30 min while both were considerably inactivated after 30 min at 45°C. Therefore, we conclude that the carbohydrate moiety plays no significant role in the enzymatic function of P. amagasakiense GOD.