Purification and characterization of two lignin peroxidase isozymes produced by Bjerkandera sp. strain BOS55.
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 H2O2 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 Km for H2O2 strongly decreased with increasing pH. As a result of this the catalytic efficiency (TN/Km) calculated on the basis of the Km for H2O2 in the oxidation of veratryl alcohol was constant over wide pH range.
ten Have
R
R
Department of Food Technology and Nutrition, Wageningen Agricultural University, The Netherlands. Rimko.tenHave@algemeen.im.wau.nl
Hartmans
S
S
Teunissen
P J
PJ
Field
J A
JA
D000595:Amino Acid Sequence; D001487:Basidiomycota / Q000201:enzymology*; D007527:Isoenzymes / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D010544:Peroxidases / Q000302:isolation & purification* / Q000378:metabolism
D007527:Isoenzymes; D010544:Peroxidases; C042858:lignin peroxidase