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Literature summary for 3.2.1.2 extracted from

  • 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 (2008), Plant Cell, 20, 1040-1058.
    View publication on PubMedView publication on EuropePMC

Cloned(Commentary)

Cloned (Comment) Organism
expressed in Escherichia coli Arabidopsis thaliana

Protein Variants

Protein Variants Comment Organism
E380Q structural modeling of BAM-9. BAM-4 and BAM-9 are also substituted at position 342 on the inner loop Arabidopsis thaliana
E380R 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 Arabidopsis thaliana
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 Arabidopsis thaliana

Localization

Localization Comment Organism GeneOntology No. Textmining
chloroplast BAM-1, BAM-2, BAM-3, BAM-4 Arabidopsis thaliana 9507
-

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
54600
-
BAM-2 Arabidopsis thaliana
55500
-
BAM-3 Arabidopsis thaliana
55500
-
calculated, BAM-2 Arabidopsis thaliana
55800
-
calculated, BAM-3 Arabidopsis thaliana
59500
-
calculated, BAM-1 Arabidopsis thaliana
67500
-
BAM-1 Arabidopsis thaliana

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
amylopectin + H2O Arabidopsis thaliana
-
beta-maltose + ?
-
?
maltotetraose + H2O Arabidopsis thaliana
-
?
-
?
starch + H2O Arabidopsis thaliana
-
beta-maltose
-
?

Organism

Organism UniProt Comment Textmining
Arabidopsis thaliana
-
ecotype Columbia
-

Purification (Commentary)

Purification (Comment) Organism
affinity chromatography, to near homogeneity using Glutathione-Sepharose 4B Arabidopsis thaliana

Source Tissue

Source Tissue Comment Organism Textmining
leaf
-
Arabidopsis thaliana
-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
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 Arabidopsis thaliana

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
amylopectin + H2O
-
Arabidopsis thaliana beta-maltose + ?
-
?
maltotetraose + H2O
-
Arabidopsis thaliana ?
-
?
starch + H2O
-
Arabidopsis thaliana beta-maltose
-
?

Synonyms

Synonyms Comment Organism
BAM-1 chloroplastic Arabidopsis thaliana
BAM-2 chloroplastic Arabidopsis thaliana
BAM-3 chloroplastic Arabidopsis thaliana
BAM-5
-
Arabidopsis thaliana
BAM-6
-
Arabidopsis thaliana
BAM-7
-
Arabidopsis thaliana
BAM-8
-
Arabidopsis thaliana
BAM-9
-
Arabidopsis thaliana
beta-amylase
-
Arabidopsis thaliana
More BAM-4 is chloroplastic, expressed in Escherichia coli with no beta-amylase activity, probably lost its catalytic capacity during evolution Arabidopsis thaliana

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
6 7
-
Arabidopsis thaliana