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Purification and characterization of two lignin peroxidase isozymes produced by Bjerkandera sp. strain BOS55
Author(s) -
ten Have Rimko,
Hartmans Sybe,
Teunissen Pauline J.M,
Field Jim A
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00044-1
Subject(s) - isozyme , lignin peroxidase , peroxidase , lignin , chemistry , biochemistry , enzyme , organic chemistry
The white‐rot fungus Bjerkandera sp. strain BOS55 excretes at least seven lignin peroxidase (LiP) isozymes. Two of these, LiP‐2 and LiP‐5 (molecular weight 40–42 kDa), were purified to homogeneity. Both isozymes had the same N‐terminal amino acid sequence which showed strong homology with LiP isozymes produced by other white‐rot fungi. The kinetics of both isozymes were similar. LiP‐5 oxidized veratryl alcohol optimally only in the presence of H 2 O 2 near pH 3.0 (16.7 U/mg) and LiP‐2 did this below pH 2.5 (33.8 U/mg). Also at normal physiological pHs for fungal growth (pH 5.0–6.5) both isozymes were still active. Further characterization of LiP‐2 and LiP‐5 revealed that the K m for H 2 O 2 strongly decreased with increasing pH. As a result of this the catalytic efficiency (TN/ K m ) calculated on the basis of the K m for H 2 O 2 in the oxidation of veratryl alcohol was constant over wide pH range.