{PDOC00414}
{PS00506; BETA_AMYLASE_1}
{PS00679; BETA_AMYLASE_2}
{BEGIN}
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* Beta-amylase active sites *
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Beta-amylase (EC  3.2.1.2)  [1,2]  is  an  enzyme  that  hydrolyzes 1,4-alpha-
glucosidic linkages in starch-type polysaccharide substrates  so  as to remove
successive maltose units from the  non-reducing  ends  of  the  chains.  Beta-
amylase is present in certain bacteria as well as in plants.

Three highly  conserved sequence regions are found in all known beta-amylases.
The first of these regions is located in the N-terminal section of the enzymes
and contains an aspartate  which is known [3] to be involved in the catalytic
mechanism. The  second, located in a more central location, is centered around
a glutamate  which  is  also involved [4] in the catalytic mechanism.   We use
both regions as signature patterns.

-Consensus pattern: H-x-C-G-G-N-V-G-D
                    [D is an active site residue]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Consensus pattern: G-x-[SA]-G-E-[LIVM]-R-Y-P-S-Y
                    [E is an active site residue]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Note: These proteins belong to family 14  in  the  classification of glycosyl
 hydrolases [5,E1].

-Last update: November 1997 / Text revised.

[ 1] Mikami B., Morita Y., Fukazawa C.
     "Primary structure and function of beta-amylase."
     Seikagaku 60:211-216(1988).
     PubMed=2457058
[ 2] Friedberg F., Rhodes C.
     "Segments of amino acid sequence similarity in beta-amylases."
     Protein Seq. Data Anal. 1:499-501(1988).
     PubMed=2464171
[ 3] Nitta Y., Isoda Y., Toda H., Sakiyama F.
     "Identification of glutamic acid 186 affinity-labeled by
     2,3-epoxypropyl alpha-D-glucopyranoside in soybean beta-amylase."
     J. Biochem. 105:573-576(1989).
     PubMed=2474529
[ 4] Totsuka A., Nong V.H., Kadokawa H., Kim C.-S., Itoh Y., Fukazawa C.
     "Residues essential for catalytic activity of soybean beta-amylase."
     Eur. J. Biochem. 221:649-654(1994).
     PubMed=8174545
[ 5] Henrissat B.
     "A classification of glycosyl hydrolases based on amino acid sequence
     similarities."
     Biochem. J. 280:309-316(1991).
     PubMed=1747104
[E1] https://www.uniprot.org/docs/glycosid

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