Properties of laccase purified from nitrogen limited culture of white-rotfungus Coriolus hirsutus

摘要

Laccase produced by nitrogen-limited culture of Coriolus hirsutus was purified to electrophoretic homogeneity (133-fold) with an overall yield of 40 %. The molecular mass of the enzyme was determined as 82 kDa by SDS-PAGE and 80 kDa using gel filtration. It had a pI of 3.50. With ferulic acid and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonate) (ABTS) as the substrate, the enzyme had optimal activity at pH 4.0 and 2.5, respectively. The enzyme was stable in the range pH 5.5 to 7.0 at 30 degrees C for 1 h. The enzyme was optimally active at 70 degrees C and it lost all activity within 15 min at 80 degrees C. The apparent K-m value of enzyme toward ABTS was 67 degrees M and had highest affinity toward sinapinic acid. The enzyme was totally inhibited by 0.01 mM cysteine.