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L‐Lysine α‐oxidase from Trichoderma viride i4. Purification and characterization
Author(s) -
Weber Ekkehard,
Tonder Karin,
Reinbothe Christiane,
Unverhau Kerstin,
Weide Heinz,
Aurich Harald
Publication year - 1994
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.3620340411
Subject(s) - trichoderma viride , chemistry , isoelectric point , lysine , molecular mass , size exclusion chromatography , sephadex , enzyme , hydrogen peroxide , biochemistry , oxidase test , chromatography , covalent bond , amino acid , organic chemistry , food science
A L‐lysine α‐oxidase (LOD) has been purified to homogeneity in a two‐step procedure with 300‐fold enrichment and 60% recovery from the culture extract of Trichoderma viride i4. The enzyme catalyzes the reaction between L‐lysine and molecular oxygen forming 2‐oxo‐6‐aminocaproate, ammonia and hydrogen peroxide. Numerous substrates have been tested. The K m value for L‐lysine was found to be 0.026 mM. Its apparent molecular mass is 110000 Da when determined by gel filtration on Sephadex G‐200, the estimated molecular weight of the subunits being 55000 Da in the SDS‐PAGE. The enzyme is a glycoprotein and shows absorption maxima at 276, 386 and 463 nm. It was found to contain 1 mol of FAD per subunit. The coenzyme is bound non‐covalently. Its isoelectric point is at pH 4.3. The enzyme is stable at extreme pH values, at relatively high temperatures and in diluted hydrogen peroxide. The enzyme described here differs from two other known L‐lysine oxidases previously characterized with regard to its amino acid composition and its substrate specificity.