The enzyme contained 510 amino acid residues and was a single polypeptide of a molecular size of 63 kDa. It contained 11% carbohydrate that is consistent with other laccases (Coll et al. 1993). The first 10 amino acids at the N-terminal were A, I, G, P, V, A, B, L, T, and L and differed from the enzyme from P. cinnabarinus PB, also isolated in Australia, only in the B for D in residue 7 (Eggert et al. 1996). It also showed considerable homology to the laccase of P. ostreatus (Youn et al. 1995), C. (Trametes) versicolor (Bourbonnais et al. 1995), and Coriolus hirsutus (Kojima et al. 1990).
A major band and two minor bands were observed at pH 3 and pH 2.85 and 2.65, respectively, on isoelectric focusing (IEF). Each band stained the laccase substrate guaiacol (10 mM). One band only, corresponding to laccase activity, was obtained on electrophoresis (4-20% gradient gel) under nondenaturing conditions. This band, stained with 10 mM guaiacol, corresponded with the co-electrophoresis protein band.
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