Isolation and Study of Some Properties of Laccase from the Basidiomycetes Cerrena maxima

O. V. Koroleva^1*, I. S. Yavmetdinov¹, S. V. Shleev¹, E. V. Stepanova¹, and V. P. Gavrilova²

¹Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, Moscow, 117071 Russia; fax: (095) 954-2732; E-mail: alena_koroleva@hotmail.com

²Komarov Botanical Institute, Russian Academy of Sciences, ul. Prof. Popova 2, St. Petersburg, 197022 Russia; fax: (812) 234-4512; E-mail: Valeria@VG2438.spb.edu

^* To whom correspondence should be addressed.

Received August 7, 2000; Revision received October 20, 2000

---

A new strain producing extracellular laccase (Cerrena maxima 0275) was found by screening of isolates of Basidiomycetes, and the dynamics of laccase biosynthesis by this strain was studied. The enzyme was purified to homogeneity. The molecular weight of the enzyme is 57 kD, and its pI is 3.5. The activity is constant at pH values in the range 3.0-5.0. The temperature optimum for activity is 50^oC. The thermal stability of the laccase was studied. The catalytic and Michaelis constants for catechol, hydroquinone, sinapinic acid, and K₄Fe(CN)₆ were determined. The standard redox potential of type 1 copper in the enzyme is 750 ± 5 mV. Thus, the investigated laccase is a high redox potential laccase.

---

KEY WORDS: Cerrena maxima, laccase, redox potential, pH optimum, isoelectric point, Michaelis constant

---