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Information on EC 3.2.1.2 - beta-amylase and Organism(s) Arabidopsis thaliana and UniProt Accession Q9LIR6
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3.2.1.2 beta-amylaseIUBMB Comments
Acts on starch, glycogen and related polysaccharides and oligosaccharides producing beta-maltose by an inversion. The term 'beta'' relates to the initial anomeric configuration of the free sugar group released and not to the configuration of the linkage hydrolysed.
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Word Map
- 3.2.1.2
- starch
- alpha-amylase
- maltose
- barley
- potato
- soybean
-
sweet
- amylopectin
-
amylolytic
- glucoamylase
- endosperm
- hordeum
- amylases
- pullulanase
-
debranching
- dextrin
- nutrition
- maltotetraose
- thermosulfurogenes
- isoamylase
-
beta-limit
-
starch-degrading
- amyloglucosidase
- polymyxa
- maltotriose
- maltopentaose
-
granule-bound
- alpha-cyclodextrin
-
extrachloroplastic
- industry
-
sporamin
- molecular biology
- brewing
The taxonomic range for the selected organisms is: Arabidopsis thaliana
The expected taxonomic range for this enzyme is: Eukaryota, Bacteria, Archaea
The expected taxonomic range for this enzyme is: Eukaryota, Bacteria, Archaea
Reaction Schemes
Synonyms
beta-amylase, arath, spoii, tr-bamy, beta amylase, ct-bmy, bam-2, beta-amylase 1, bam-8, glycogenase, 
more
topSYNONYM 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
(1-4)-alpha-D-glucan maltohydrolase
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1,4-alpha-D-glucan maltohydrolase
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amylase, beta-
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BAM3
beta amylase
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BMY
glycogenase
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-
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saccharogen amylase
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-
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saccharogenamylase
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-
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-
additional information
-
BAM-4 is chloroplastic, expressed in Escherichia coli with no beta-amylase activity, probably lost its catalytic capacity during evolution
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
Hydrolysis of (1->4)-alpha-D-glucosidic linkages in polysaccharides so as to remove successive maltose units from the non-reducing ends of the chains
general acid-base catalytic reaction mechanism
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PATHWAY SOURCE
PATHWAYS
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-, -
SYSTEMATIC NAME
IUBMB Comments
4-alpha-D-glucan maltohydrolase
Acts on starch, glycogen and related polysaccharides and oligosaccharides producing beta-maltose by an inversion. The term 'beta'' relates to the initial anomeric configuration of the free sugar group released and not to the configuration of the linkage hydrolysed.
CAS REGISTRY NUMBER
COMMENTARY
9000-91-3
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SUBSTRATE
PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
4-nitrophenyl maltopentaose + H2O
4-nitrophenol + maltopentaose
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-
-
?
starch + H2O
?
in vitro breakdown of semicrystalline starch particles by beta-amylases increases significantly if they act together with glucan, water dikinase
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-
?
starch + H2O
?
in vitro breakdown of semicrystalline starch particles by beta-amylases increases significantly if they act together with glucan, water dikinase
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-
?
starch + H2O
maltose + ?
the isozyme is involved in leaf starch degradation
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-
?
starch + H2O
maltose + ?
enzyme induction upon a cold shock at 4°C leads to starch-dependent maltose accumulation, which might be required for protection of the photosynthetic electron transport chain and sensitization of PSII during freezing, maltose influences the carbohydrate metabolism, overview
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-
?
starch + H2O
maltose + ?
-
role of beta-amylase in starch breakdown during temperature stress, product maltose acts as a cryoprotectant and precursor of soluble sugar metabolism, overview
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-
?
additional information
?
-
the isozyme TR-BAMY is redox- and thioredoxin-regulated involving residues C470 and C32 forming a disulfide bridge, the precursor enzyme conatining the transit pepetide is inactive
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-
?
additional information
?
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the isozyme TR-BAMY is redox- and thioredoxin-regulated involving residues C470 and C32 forming a disulfide bridge, the precursor enzyme conatining the transit pepetide is inactive
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-
?
additional information
?
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plants mechanism of cold adaptation, enzyme regulation by phytohormones, light, and by abiotic stess, e.g. by osmotic, cold, salt, and drought stress, the enzyme is also regulated by the circadian clock, detailed overview
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-
?
NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
starch + H2O
maltose + ?
the isozyme is involved in leaf starch degradation
-
-
?
starch + H2O
maltose + ?
enzyme induction upon a cold shock at 4°C leads to starch-dependent maltose accumulation, which might be required for protection of the photosynthetic electron transport chain and sensitization of PSII during freezing, maltose influences the carbohydrate metabolism, overview
-
-
?
starch + H2O
maltose + ?
-
role of beta-amylase in starch breakdown during temperature stress, product maltose acts as a cryoprotectant and precursor of soluble sugar metabolism, overview
-
-
?
additional information
?
-
the isozyme TR-BAMY is redox- and thioredoxin-regulated involving residues C470 and C32 forming a disulfide bridge, the precursor enzyme conatining the transit pepetide is inactive
-
-
?
additional information
?
-
the isozyme TR-BAMY is redox- and thioredoxin-regulated involving residues C470 and C32 forming a disulfide bridge, the precursor enzyme conatining the transit pepetide is inactive
-
-
?
additional information
?
-
-
plants mechanism of cold adaptation, enzyme regulation by phytohormones, light, and by abiotic stess, e.g. by osmotic, cold, salt, and drought stress, the enzyme is also regulated by the circadian clock, detailed overview
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-
?
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
additional information
the 41 amino acid transit peptide inhibits isozyme TR-BAMY
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additional information
the 41 amino acid transit peptide inhibits isozyme TR-BAMY
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ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
thioredoxin
thioredocins f1, m1, and y1, the isozyme TR-BAMY is positively thioredoxin-regulated
additional information
the enzyme requires reducing conditions for full activity
-
additional information
the enzyme requires reducing conditions for full activity
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additional information
-
cold stress activates the chloroplastic isozyme by 5fold at 3°C
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additional information
the enzyme is induced during low temperature stress at 4°C
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SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
additional information
additional information
-
BAM-2 specific activity is 25fold lower than that of BAM-3 and 50fold lower than that of BAM-1. No activity is detectable for recombinant BAM-4 protein
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
additional information
additional information
the isozyme TR-BAMY shifts between an active and an inactive form dependent on the pH
additional information
the isozyme TR-BAMY shifts between an active and an inactive form dependent on the pH
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
TEMPERATURE RANGE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
additional information
freezing tolerance of recombinant plants, overview
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
gene At3g23920/F14O13_11, isozyme TR-BAMY; contains six extrachloroplastic isozymes, and three plastid-targeted isozymes
SwissProt
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SOURCE
additional information
-
BAM4 is preferentially expressed in vascular tissues in source and sink organs
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY
GeneOntology No.
LITERATURE
SOURCE
plastid-targeted isozyme TR-BAMY, contains a plastid transit peptide of 41 amino acids
plastid-targeted isozyme TR-BAMY, contains a plastid transit peptide of 41 amino acids
plastid-targeted isozyme CT-BAMY, contains a plastid transit peptide
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable).
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable). BAM1_ARATH
575
0
63762
Swiss-Prot
Chloroplast (Reliability: 5)
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
64000
recombinant precursor isozyme TR-BAMY, gel filtration
55500
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
monomer
1 * 60000, recombinant mature isozyme TR-BAMY, SDS-PAGE, 1 * 64000, recombinant precursor isozyme TR-BAMY, SDS-PAGE
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
C148S
site-directed mutagenesis, the mutant shows a redox sensitivity similar to the wild-type enzyme
C206S
site-directed mutagenesis, the mutant shows a redox sensitivity similar to the wild-type enzyme
C261S
site-directed mutagenesis, the mutant shows a redox sensitivity similar to the wild-type enzyme
C32S
site-directed mutagenesis, the mutant shows 70% impaired redox sensitivity compared to the wild-type enzyme
C399S
site-directed mutagenesis, the mutant shows a redox sensitivity similar to the wild-type enzyme
C413S
site-directed mutagenesis, the mutant shows a redox sensitivity similar to the wild-type enzyme
C470S
site-directed mutagenesis, the mutant shows 70% impaired redox sensitivity compared to the wild-type enzyme
C506S
site-directed mutagenesis, the mutant shows a redox sensitivity similar to the wild-type enzyme
E380Q
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structural modeling of BAM-9. BAM-4 and BAM-9 are also substituted at position 342 on the inner loop
E380R
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structural modeling of the BAM-4 active site predicts an inactive protein. BAM-4 and BAM-9 are also substituted at position 342 on the inner loop
additional information
additional information
construction of BMY8 knockout plants, and of BMY8 RNAi plants, enzyme induction upon a cold shock leads to starch-dependent maltose accumulation, which can be prevented by RNA interference, phenotype and starch content of recombinant BMY8 RNAi plants, freezing tolerance of recombinant plants, overview
additional information
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knockout plants of palstidic isozymes BMY6 and BMY8/CT-BMY leads to a starch-excess phenotype in leaves
additional information
-
bam1, T-DNA insertion mutation, has no elevated starch levels and no lower nighttime maltose levels than the wild type. Mutant bam2, T-DNA insertion mutation. Mutant bam3, formation of a mutant line via the Arabidopsis TILLING Program, has elevated starch levels and lower nighttime maltose levels than the wild type. Mutant bam4, T-DNA insertion mutation, has elevated starch levels. Double mutant bam1 bam3, more severe phenotype than bam3. Total beta-amylase activity is reduced in leaves of bam1 and bam3 mutants but not in bam2 and bam4 mutants
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
native isozyme partially by chloroplast purification, recombinant mature isozyme TR-BAMY and recombinant mutant enzymes from Escherichia coli
affinity chromatography, to near homogeneity using Glutathione-Sepharose 4B
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CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
isozyme TR-BAMY, DNA and amino acid sequence determination and analysis, functional expression of mature isozyme TR-BAMY and of mutant enzymes in Escherichia coli strains HB101 and BL21(DE3), transient expression of GFP-tagged isozyme TR-BAMY in Nicotiana tabacum protoplasts with exclusive association to the chloroplasts
DNA sequence determination, construction of BMY8 knockout plants, and of BMY8 RNAi plants
isozyme CT-BAMY, DNA and amino acid sequence determination and analysis
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Kaplan, F.; Sung, D.Y.; Guy, C.L.
Roles of beta-amylase and starch breakdown during temperature stress
Physiol. Plant.
126
120-128
2006
Arabidopsis thaliana, Glycine max, Hordeum vulgare, Solanum tuberosum
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Kaplan, F.; Guy, C.L.
RNA interference of Arabidopsis beta-amylase8 prevents maltose accumulation upon cold shock and increases sensitivity of PSII photochemical efficiency to freezing stress
Plant J.
44
730-743
2005
Arabidopsis thaliana (O23553)
Sparla, F.; Costa, A.; Lo Schiavo, F.; Pupillo, P.; Trost, P.
Redox regulation of a novel plastid-targeted beta-amylase of Arabidopsis
Plant Physiol.
141
840-850
2006
Arabidopsis thaliana (O23553), Arabidopsis thaliana (Q9LIR6)
Edner, C.; Li, J.; Albrecht, T.; Mahlow, S.; Hejazi, M.; Hussain, H.; Kaplan, F.; Guy, C.; Smith, S.M.; Steup, M.; Ritte, G.
Glucan, water dikinase activity stimulates breakdown of starch granules by plastidial beta-amylases
Plant Physiol.
145
17-28
2007
Arabidopsis thaliana (O23553), Arabidopsis thaliana (Q9LIR6)
Fulton, D.C.; Stettler, M.; Mettler, T.; Vaughan, C.K.; Li, J.; Francisco, P.; Gil, M.; Reinhold, H.; Eicke, S.; Messerli, G.; Dorken, G.; Halliday, K.; Smith, A.M.; Smith, S.M.; Zeeman, S.C.
Beta-AMYLASE4, a noncatalytic protein required for starch breakdown, acts upstream of three active beta-amylases in Arabidopsis chloroplasts
Plant Cell
20
1040-1058
2008
Arabidopsis thaliana
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