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Information on EC 3.2.1.68 - isoamylase and Organism(s) Arabidopsis thaliana and UniProt Accession O04196
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EC Tree
3.2.1.68 isoamylaseIUBMB Comments
Also readily hydrolyses amylopectin. Differs from EC 3.2.1.41 (pullulanase) and EC 3.2.1.142 (limit dextrinase) by its inability to hydrolyse pullulan, and by limited action on alpha-limit dextrins. Maltose is the smallest sugar it can release from an alpha-(1->6)-linkage.
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Word Map
- 3.2.1.68
-
salivary
- lipase
- amylopectin
-
hyperamylasemia
- isoenzymes
- alpha-amylase
- pancreas
- phosphorylase
- amylose
- pullulanase
-
exocrine
- abdominal
- endosperm
- dextrin
- glucans
- phytoglycogen
-
salivary-type
-
nonpancreatic
-
amylolytic
- pseudocysts
-
s-type
- beta-amylase
-
dextrinase
-
pancreatic-type
-
macroamylasemia
- amylo-1,6-glucosidase
-
extrapancreatic
-
glucanotransferase
-
phadebas
- analysis
- 4-alpha-glucanotransferase
- nutrition
- maltooligosaccharides
-
glycogenolytic
- maltotriose
-
alpha-1,4
- isomaltose
- alpha-glucans
-
waxy
-
hyperenzymemia
- glycogenin
-
granule-bound
- medicine
- food industry
- synthesis
- degradation
- detergent
The taxonomic range for the selected organisms is: Arabidopsis thaliana
The expected taxonomic range for this enzyme is: Bacteria, Eukaryota, Archaea
The expected taxonomic range for this enzyme is: Bacteria, Eukaryota, Archaea
Reaction Schemes
Synonyms
isoamylase, glycogen debranching enzyme, starch debranching enzyme, alpha-1,6-glucosidase, glycogen-debranching enzyme, isoamylase1, isoamylase 3, atisa3, isoamylase-type debranching enzyme, atisa1, 
more
topSYNONYM 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
AtISA3
debranching enzyme
-
-
-
-
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
hydrolysis of O-glycosyl bond
hydrolysis of O-glycosyl bond
-
-
-
-
PATHWAY SOURCE
PATHWAYS
BRENDA
-
-, -, -
SYSTEMATIC NAME
IUBMB Comments
glycogen 6-alpha-D-glucanohydrolase
Also readily hydrolyses amylopectin. Differs from EC 3.2.1.41 (pullulanase) and EC 3.2.1.142 (limit dextrinase) by its inability to hydrolyse pullulan, and by limited action on alpha-limit dextrins. Maltose is the smallest sugar it can release from an alpha-(1->6)-linkage.
CAS REGISTRY NUMBER
COMMENTARY
9067-73-6
-
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
additional information
?
-
AtISA1 and AtISA2 are required for the production of a functional isoamylase-type of debranching enzyme named Iso1, the major isoamylase found in leaves. The absence of Iso1 leads to an 80% decrease in the starch content and to accumulation of water-soluble polysaccharides whose structure is similar to glycogen
-
-
?
additional information
?
-
AtISA1 and AtISA2 are required for the production of a functional isoamylase-type of debranching enzyme named Iso1, the major isoamylase found in leaves. The absence of Iso1 leads to an 80% decrease in the starch content and to accumulation of water-soluble polysaccharides whose structure is similar to glycogen
-
-
?
additional information
?
-
AtISA1 and AtISA2 are required for the production of a functional isoamylase-type of debranching enzyme named Iso1, the major isoamylase found in leaves. The absence of Iso1 leads to an 80% decrease in the starch content and to accumulation of water-soluble polysaccharides whose structure is similar to glycogen
-
-
?
additional information
?
-
synthesis of amylopectin and phytoglycogen by associated and separated ISA1 and ISA2, respectively, overview
-
-
?
additional information
?
-
synthesis of amylopectin and phytoglycogen by associated and separated ISA1 and ISA2, respectively, overview
-
-
?
additional information
?
-
AtISA1 and AtISA2 are required for the production of a functional isoamylase-type of debranching enzyme named Iso1, the major isoamylase found in leaves. The absence of Iso1 leads to an 80% decrease in the starch content and to accumulation of water-soluble polysaccharides whose structure is similar to glycogen
-
-
?
additional information
?
-
AtISA1 and AtISA2 are required for the production of a functional isoamylase-type of debranching enzyme named Iso1, the major isoamylase found in leaves. The absence of Iso1 leads to an 80% decrease in the starch content and to accumulation of water-soluble polysaccharides whose structure is similar to glycogen
-
-
?
additional information
?
-
AtISA1 and AtISA2 are required for the production of a functional isoamylase-type of debranching enzyme named Iso1, the major isoamylase found in leaves. The absence of Iso1 leads to an 80% decrease in the starch content and to accumulation of water-soluble polysaccharides whose structure is similar to glycogen
-
-
?
additional information
?
-
-
AtISA1/AtISA2 isoamylase influences glucan branching pattern
-
-
?
additional information
?
-
-
glucan debranching occurs primarily at the granule surface via ISA3, but in its absence soluble branched glucans are debranched in the stroma via limit dextrinase. Isoamylase acts at the surface of the starch granule. Atisa3 mutants have more leaf starch and a slower rate of starch breakdown than wild-type plants
-
-
?
additional information
?
-
mutant lines carrying a defect in AtISA3 display a strong starch-excess phenotype at the end of both the light and the dark phases accompanied by a small modification of the amylopectin structure
-
-
?
additional information
?
-
mutant lines carrying a defect in AtISA3 display a strong starch-excess phenotype at the end of both the light and the dark phases accompanied by a small modification of the amylopectin structure
-
-
?
additional information
?
-
mutant lines carrying a defect in AtISA3 display a strong starch-excess phenotype at the end of both the light and the dark phases accompanied by a small modification of the amylopectin structure
-
-
?
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
additional information
?
-
AtISA1 and AtISA2 are required for the production of a functional isoamylase-type of debranching enzyme named Iso1, the major isoamylase found in leaves. The absence of Iso1 leads to an 80% decrease in the starch content and to accumulation of water-soluble polysaccharides whose structure is similar to glycogen
-
-
?
additional information
?
-
AtISA1 and AtISA2 are required for the production of a functional isoamylase-type of debranching enzyme named Iso1, the major isoamylase found in leaves. The absence of Iso1 leads to an 80% decrease in the starch content and to accumulation of water-soluble polysaccharides whose structure is similar to glycogen
-
-
?
additional information
?
-
AtISA1 and AtISA2 are required for the production of a functional isoamylase-type of debranching enzyme named Iso1, the major isoamylase found in leaves. The absence of Iso1 leads to an 80% decrease in the starch content and to accumulation of water-soluble polysaccharides whose structure is similar to glycogen
-
-
?
additional information
?
-
synthesis of amylopectin and phytoglycogen by associated and separated ISA1 and ISA2, respectively, overview
-
-
?
additional information
?
-
synthesis of amylopectin and phytoglycogen by associated and separated ISA1 and ISA2, respectively, overview
-
-
?
additional information
?
-
AtISA1 and AtISA2 are required for the production of a functional isoamylase-type of debranching enzyme named Iso1, the major isoamylase found in leaves. The absence of Iso1 leads to an 80% decrease in the starch content and to accumulation of water-soluble polysaccharides whose structure is similar to glycogen
-
-
?
additional information
?
-
AtISA1 and AtISA2 are required for the production of a functional isoamylase-type of debranching enzyme named Iso1, the major isoamylase found in leaves. The absence of Iso1 leads to an 80% decrease in the starch content and to accumulation of water-soluble polysaccharides whose structure is similar to glycogen
-
-
?
additional information
?
-
AtISA1 and AtISA2 are required for the production of a functional isoamylase-type of debranching enzyme named Iso1, the major isoamylase found in leaves. The absence of Iso1 leads to an 80% decrease in the starch content and to accumulation of water-soluble polysaccharides whose structure is similar to glycogen
-
-
?
additional information
?
-
-
AtISA1/AtISA2 isoamylase influences glucan branching pattern
-
-
?
additional information
?
-
-
glucan debranching occurs primarily at the granule surface via ISA3, but in its absence soluble branched glucans are debranched in the stroma via limit dextrinase. Isoamylase acts at the surface of the starch granule. Atisa3 mutants have more leaf starch and a slower rate of starch breakdown than wild-type plants
-
-
?
additional information
?
-
mutant lines carrying a defect in AtISA3 display a strong starch-excess phenotype at the end of both the light and the dark phases accompanied by a small modification of the amylopectin structure
-
-
?
additional information
?
-
mutant lines carrying a defect in AtISA3 display a strong starch-excess phenotype at the end of both the light and the dark phases accompanied by a small modification of the amylopectin structure
-
-
?
additional information
?
-
mutant lines carrying a defect in AtISA3 display a strong starch-excess phenotype at the end of both the light and the dark phases accompanied by a small modification of the amylopectin structure
-
-
?
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SOURCE
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY
GeneOntology No.
LITERATURE
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
malfunction
loss of isozyme ISA1 or ISA2 causes phytoglycogen accumulation
physiological function
the ISA1 class of DBE is the one primarily associated with amylopectin synthesis
additional information
additional information
Arabidopsis thaliana subunit ISA1 requires subunit ISA2 as a partner for enzymatic function. Images of purified starch granules of wild-type and mutant lines, overview. Recombinant AtISA1 is capable of enzymatic activity if mixed with recombinant AtISA2 but does not display such function on its own
additional information
Arabidopsis thaliana subunit ISA1 requires subunit ISA2 as a partner for enzymatic function. Images of purified starch granules of wild-type and mutant lines, overview. Recombinant AtISA1 is capable of enzymatic activity if mixed with recombinant AtISA2 but does not display such function on its own
additional information
isozyme ISA1 interacts with its homologue ISA2, but no evidence for interaction with other starch biosynthetic enzymes. ISA1 and ISA2 form a heteromultimeric enzyme with ISA1 being the catalytic subunit and ISA2 subunit not catalytically active
additional information
isozyme ISA1 interacts with its homologue ISA2, but no evidence for interaction with other starch biosynthetic enzymes. ISA1 and ISA2 form a heteromultimeric enzyme with ISA1 being the catalytic subunit and ISA2 subunit not catalytically active
additional information
Arabidopsis thaliana subunit ISA1 requires subunit ISA2 as a partner for enzymatic function. Images of purified starch granules of wild-type and mutant lines, overview
additional information
Arabidopsis thaliana subunit ISA1 requires subunit ISA2 as a partner for enzymatic function. Images of purified starch granules of wild-type and mutant lines, overview
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). ISOA1_ARATH
783
0
89481
Swiss-Prot
Chloroplast (Reliability: 3)
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
150000
x * 150000, ISA1 and ISA2 as stable dimer, SDS-PAGE
additional information
additional information
comparable mobility in the native PAGE of native enzyme recombinnat enzyme complex
additional information
comparable mobility in the native PAGE of native enzyme recombinnat enzyme complex
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
additional information
-
ISA1 and ISA2 proteins are subunits of the same enzyme
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
D367A
site-directed mutagenesis of the catalytic nucleophile Asp-367 in ISA1, the mutation abolishes the catalytic activity of the enzyme complex
additional information
additional information
construction of single mutant line isa1-1 by T-DNA insertion mutagenesis. The isa1-1 isa2-2 double mutant line is obtained by a cross between the two corresponding single mutants and screening of the progeny by PCR amplification of genomic DNA using a T-DNA end primer and gene-specific primers. The phenotype of the isa1-1 isa2-2 double mutant is complemented but the ZmISA1 activity, Zea mays ISA1 subunit is expressed via transfection with Agrobacterium tumefaciens strain GV3101 in Arabidopsis thaliana lacking endogenous ISA1 or lacking both native ISA1 and ISA2. The maize protein functions in Arabidopsis leaves to support nearly normal starch metabolism in the absence of any native ISA1 or ISA2
additional information
construction of single mutant line isa1-1 by T-DNA insertion mutagenesis. The isa1-1 isa2-2 double mutant line is obtained by a cross between the two corresponding single mutants and screening of the progeny by PCR amplification of genomic DNA using a T-DNA end primer and gene-specific primers. The phenotype of the isa1-1 isa2-2 double mutant is complemented but the ZmISA1 activity, Zea mays ISA1 subunit is expressed via transfection with Agrobacterium tumefaciens strain GV3101 in Arabidopsis thaliana lacking endogenous ISA1 or lacking both native ISA1 and ISA2. The maize protein functions in Arabidopsis leaves to support nearly normal starch metabolism in the absence of any native ISA1 or ISA2
additional information
construction of a single mutant line isa2-2 by T-DNA insertion mutagenesis. The isa1-1 isa2-2 double mutant line is obtained by a cross between the two corresponding single mutants and screening of the progeny by PCR amplification of genomic DNA using a T-DNA end primer and gene-specific primers. The phenotype of the isa1-1 isa2-2 double mutant is complemented but the ZmISA1 activity
additional information
construction of a single mutant line isa2-2 by T-DNA insertion mutagenesis. The isa1-1 isa2-2 double mutant line is obtained by a cross between the two corresponding single mutants and screening of the progeny by PCR amplification of genomic DNA using a T-DNA end primer and gene-specific primers. The phenotype of the isa1-1 isa2-2 double mutant is complemented but the ZmISA1 activity
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
copurification of native isozymes ISA1 and ISA2 partially from leaves by gel filtration, copurification of TAP-tagged ISA1 and ISA2 from Escherichia coli strain BL21(DE3) by tandem-affinity chromatography on TEV and calmodulin, followed by gel filtration
recombinant C-terminally His8-tagged single subunit ISA1 or ISA1 in complex with His8-tagged ISA2 from Escherichia coli strain BL21(DE3) by nickel affinity chromatography
recombinant C-terminally His8-tagged single subunit ISA2 or His8-tagged ISA2 in complex with ISA1 from Escherichia coli strain BL21(DE3) by nickel affinity chromatography
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
coexpression of wild-type His-tagged ISA1 and ISA2, and of mutant D367A ISA1 with wild-type ISA2, in Escherichia coli strain BL21(DE3)
gene isa1, single expression of C-terminally His8-tagged subunit in Escherichia coli strain BL21(DE3), co-expression of untagged ISA1 subunit with C-terminally His8-tagged subunit ISA2 in Escherichia coli
gene isa2, single expression of C-terminally His8-tagged subunit in Escherichia coli strain BL21(DE3) or co-expression with untagged ISA1 subunit in Escherichia coli
into Agrobacterium tumefaciens strain GV310, GFP/GUS promoter fusion constructs for AtISA1, AtISA2, AtISA3 into Arabidopsis thaliana using the floral dip method
-
APPLICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
analysis
isoamylase-type debranching enzymes (ISAs) play an important role in determining starch structure
analysis
-
bioinformatics, microarray and reporter gene analyses reveal that AtISA1 and AtISA2, AtISA2 and AtISA3 or AtISA1, AtISA2 and AtISA3 are coexpressed under certain conditions
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Delatte, T.; Umhang, M.; Trevisan, M.; Eicke, S.; Thorneycroft, D.; Smith, S.M.; Zeeman, S.C.
Evidence for distinct mechanisms of starch granule breakdown in plants
J. Biol. Chem.
281
12050-12059
2006
Arabidopsis thaliana
Delatte, T.; Trevisan, M.; Parker, M.L.; Zeeman, S.C.
Arabidopsis mutants Atisa1 and Atisa2 have identical phenotypes and lack the same multimeric isoamylase, which influences the branch point distribution of amylopectin during starch synthesis
Plant J.
41
815-830
2005
Arabidopsis thaliana
Wattebled, F.; Dong, Y.; Dumez, S.; Delvalle, D.; Planchot, V.; Berbezy, P.; Vyas, D.; Colonna, P.; Chatterjee, M.; Ball, S.; D'Hulst, C.
Mutants of Arabidopsis lacking a chloroplastic isoamylase accumulate phytoglycogen and an abnormal form of amylopectin
Plant Physiol.
138
184-195
2005
Arabidopsis thaliana (O04196), Arabidopsis thaliana (Q8L735), Arabidopsis thaliana (Q9M0S5)
Li, L.; Ilarslan, H.; James, M.G.; Myers, A.M.; Wurtele, E.S.
Genome wide co-expression among the starch debranching enzyme genes AtISA1, AtISA2, and AtISA3 in Arabidopsis thaliana
J. Exp. Bot.
58
3323-3342
2007
Arabidopsis thaliana
Facon, M.; Lin, Q.; Azzaz, A.M.; Hennen-Bierwagen, T.A.; Myers, A.M.; Putaux, J.L.; Roussel, X.; DHulst, C.; Wattebled, F.
Distinct functional properties of isoamylase-type starch debranching enzymes in monocot and dicot leaves
Plant Physiol.
163
1363-1375
2013
Zea mays, Zea mays (B6U0X5), Arabidopsis thaliana (O04196), Arabidopsis thaliana (Q8L735), Arabidopsis thaliana Col-0 (O04196), Arabidopsis thaliana Col-0 (Q8L735)
Sundberg, M.; Pfister, B.; Fulton, D.; Bischof, S.; Delatte, T.; Eicke, S.; Stettler, M.; Smith, S.M.; Streb, S.; Zeeman, S.C.
The heteromultimeric debranching enzyme involved in starch synthesis in Arabidopsis requires both isoamylase1 and isoamylase2 subunits for complex stability and activity
PLoS ONE
8
e75223
2013
Arabidopsis thaliana (O04196), Arabidopsis thaliana (Q8L735)
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