PROGRESS CURVES - A MEAN FOR FUNCTIONAL CLASSIFICATION OF CELLULASES

The chain-end preference and processivity of the cellulases 1,4-beta-D -glucan-cellobiohydrolase I (CBHI) and 1,4-beta-D-glucan-cellobiohydro lase II (CBH II) from Trichoderma reesei and 1,4-beta-D-glucan-cellobi ohydrolase 50 (CBH 50) and 1,4-beta-D-glucan-cellobiohydrolase 58 (CBH 58) from Phanerochaete chrysosporium were studied by comparing experi mental degradation data on reducing end-labelled bacterial microcrysta lline cellulose with computer simulations of different models. Our res ults with T. reesei and P. chrysosporium cellulases show that there is a common pattern of hydrolysis for CBH-I-type enzymes and another cle arly distinguishable pattern for CBH-II-type enzymes, especially in th e initial part of the progress curve.