The microbial degradation of cellulose and xylans requires several types of
enzymes such as endoglucanases (EC 188.8.131.52), cellobiohydrolases (EC 184.108.40.206)
(exoglucanases), or xylanases (EC 220.127.116.11) [1,2]. Fungi and bacteria produces
a spectrum of cellulolytic enzymes (cellulases) and xylanases which, on the
basis of sequence similarities, can be classified into families. One of these
families is known as the cellulase family G  or as the glycosyl hydrolases
family 11 [4,E1]. The enzymes which are currently known to belong to this
family are listed below.
Aspergillus awamori xylanase C (xynC).
Bacillus circulans, pumilus, stearothermophilus and subtilis xylanase
Clostridium acetobutylicum xylanase (xynB).
Clostridium stercorarium xylanase A (xynA).
Fibrobacter succinogenes xylanase C (xynC) which consist of two catalytic
domains that both belong to family 10.
Neocallimastix patriciarum xylanase A (xynA).
Ruminococcus flavefaciens bifunctional xylanase XYLA (xynA). This protein
consists of three domains: a N-terminal xylanase catalytic domain that
belongs to family 11 of glycosyl hydrolases; a central domain composed of
short repeats of Gln, Asn an Trp, and a C-terminal xylanase catalytic
domain that belongs to family 10 of glycosyl hydrolases.
Schizophyllum commune xylanase A.
Streptomyces lividans xylanases B (xlnB) and C (xlnC).
Trichoderma reesei xylanases I and II.
Two of the conserved regions in these enzymes are centered on glutamic acid
residues which have both been shown , in Bacillus pumilis xylanase, to be
necessary for catalytic activity. We have used both regions as signature
PROSITE is copyright. It is produced by the SIB Swiss Institute
Bioinformatics. There are no restrictions on its use by non-profit
institutions as long as its content is in no way modified. Usage by and
for commercial entities requires a license agreement. For information
about the licensing scheme send an email to
or see: prosite_license.html.