ABSTRACT
PETER RAPP* and ASTRID BEERMANN In s t i tu t fu r Biochemie u n d B iotechnologie , Techrtische U niversitd t B ra unschw eig , B raunschw eig , Federal R epublic o f Germany
I. INTRODUCTION
T hree c lasses of enzym es a re found b o th in fungal and bac te ria l ce l lu lase system s: (1) l,4 -$ -D -g lu can -4 -g lu can o h y d ro la se s o r endo-1 , 4 -B -glucanases (EC 3 .2 .1 .4 ) , which random ly cleave th e in te rn a l c e l lulosic b o n d s; (2) 1 ,4 - f$-D-glucan cellobiohydrolases (EC 3 .2 .1 .9 1 ) and 1 ,4 -$ -D -glucan g lucohydro lases (EC 3 .2 .1 .7 4 ) ; th e se two exol,4 -$ -D -g lu c a n a se s bo th act from th e n o n red u c in g en d of cellulose chains o r celloo ligosaccharides, rem oving cellobiose o r g lucose; and (3) 1 ,4 -$ -D -glucosidases o r cellobiases (EC 3 .2 .1 .2 1 ) , which h y d ro lyze cellobiose and specifically cleave glucosyl u n its from th e n o n re d ucing en d s of celloo ligosaccharides. Some b ac te ria do not have ce l lob iases and cleave cellobiose and ce llo d ex trin s b y cellobiose pho sp h o ry lases (EC 2 .4 .1 .2 0 ) and ce llodex trin p h o sp hory lases (EC 2 .4 .1 .4 9 ) , re sp e c tiv e ly .
