Due to scheduled maintenance work, this service may not be available on Monday January 22nd between 08.00 am and 9.00 am CEST.
To improve security and privacy, we are moving our web pages and services from HTTP to HTTPS. To give users of web services time to transition to HTTPS, we will support separate HTTP and HTTPS services until the end of 2017. From January 2018 most HTTP traffic will be automatically redirected to HTTPS. [more...] View this page in https
The carbohydrate binding type-21 or CBM21 domain is a 90-130 amino acid
carbohydrate binding domain. The domain is named after proteins classified in
carbohydrate-binding module (CBM) family 21 and is sometimes called
starch-binding domain (SBD) [E1,1]. The CBM21 domain occurs in several
eukaryotic proteins implicated in glycogen metabolism. A glucoamylase active
site region (see <PDOC00646>) [E2] or α amylase catalytic domain [E3] can
occur C-terminal to the CBM21 domain. The CBM21 domain of Rhizopus oryzae
glucoamylase can bind to raw starch. Most conserved residues are located in a
region with a length of 35 in the N-terminal part  and in a 15-25 residue
motif II at the C-terminus of the domain [2,3,4].
Some proteins known to contain a CBM21 domain:
Mammalian protein phosphatase 1 (PP1) regulatory subunit 3A, which seems to
target PP1 to glycogen.
Mammalian protein phosphatase 1 binding protein PTG, which binds the 3 key
enzymes for the regulation of glycogen metabolism: phosphorylase kinase,
phosphorylase A and glycogen synthase.
Yeast protein phosphatase 1 regulatory subunits GAC1 and PIG1, which are
regulators of glycogen synthase.
Yeast GLC7-interacting protein 2 (GIP2), which interacts with the catalytic
subunit (GLC7) of PP1.
Yeast protein 2 interacting with GSY2 (PIG2), which interacts with glycogen
synthase 2 (GSY2), a nutritionally regulated form.
Rhizopus oryzae glucoamylase, which binds and hydrolyzes granular starch.
R. oryzae is a fungus from e.g. decaying vegetables and it causes
The profile we developed covers the entire CBM21 domain.
November 2005 / First entry.
PROSITE method (with tools and information) covered by this documentation:
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.