PALLADIUM - A NEW INHIBITOR OF CELLULASE ACTIVITIES

Palladium complexes have been shown to strongly inhibit cellobiohydrol ase I (CBH I) and endoglucanase II (EG II), two cellulases produced by Trichoderma reesei. Also inhibited were total cellulase (Avicelase) a nd beta-glucosidase (cellobiase) activities. The catalytic domain of C BH II, the second most abundant component of this cellulase, appeared less susceptible to inhibition by palladium. The inhibition was irreve rsible and could be prevented if histidine, cysteine or cystine was ad ded to the enzyme reaction mixture simultaneously with the inhibitor. The binding of CBH I to microcrystalline cellulose (Avicel) was unaffe cted by palladium. (C) 1995 Academic Press, Inc.