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Literature summary for 2.4.1.25 extracted from

  • Kaper, T.; Leemhuis, H.; Uitdehaag, J.C.; van der Veen, B.A.; Dijkstra, B.W.; van der Maarel, M.J.; Dijkhuizen, L.
    Identification of acceptor substrate binding subsites +2 and +3 in the amylomaltase from Thermus thermophilus HB8 (2007), Biochemistry, 46, 5261-5269.
    View publication on PubMed

Protein Variants

Protein Variants Comment Organism
D293A site-directed mutagenesis of the active site nucleophile, the mutant shows reduced activity with malto-oligomers compared to the wild-type enzyme Thermus thermophilus
D293N site-directed mutagenesis of the active site nucleophile, the D293N mutation reduces the pH stability of the enzyme, the mutant shows reduced activity with malto-oligomers compared to the wild-type enzyme Thermus thermophilus
D294S site-directed mutagenesis, the mutant shows highly reduced kcat and reduced activity with malto-oligomers compared to the wild-type enzyme Thermus thermophilus
D395A site-directed mutagenesis of the active site transition stabilizer, the mutant shows reduced activity with malto-oligomers compared to the wild-type enzyme Thermus thermophilus
D395N site-directed mutagenesis of the active site transition stabilizer, the mutant shows reduced activity with malto-oligomers compared to the wild-type enzyme Thermus thermophilus
E340A site-directed mutagenesis of the active site general acid/base catalyst, the mutant shows reduced activity with malto-oligomers compared to the wild-type enzyme Thermus thermophilus
E340Q site-directed mutagenesis of the active site general acid/base catalyst, the mutant shows reduced activity with malto-oligomers compared to the wild-type enzyme Thermus thermophilus
F366L site-directed mutagenesis, the mutant shows reduced kcat compared and reduced activity with malto-oligomers compared to the wild-type enzyme Thermus thermophilus

Inhibitors

Inhibitors Comment Organism Structure
acarbose a strong mixed inhibitor with almost equal competitive and uncompetitive binding constants, acarbose is both bound in the active site and at another site Thermus thermophilus

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
additional information kinetics of wild-type and mutant enzymes at pH 6.5 and 70°C, overview Thermus thermophilus

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
59337
-
x * 59337, sequence calculation Thermus thermophilus

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
additional information Thermus thermophilus Thermus thermophilus AMase is among the most efficient 4-alpha-glucanotransferases in the alpha-amylase superfamily ?
-
?
additional information Thermus thermophilus HB8 / ATCC 27634 / DSM 579 Thermus thermophilus AMase is among the most efficient 4-alpha-glucanotransferases in the alpha-amylase superfamily ?
-
?

Organism

Organism UniProt Comment Textmining
Thermus thermophilus O87172
-
-
Thermus thermophilus HB8 / ATCC 27634 / DSM 579 O87172
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
maltoheptaose + maltoheptaose
-
Thermus thermophilus ?
-
?
maltoheptaose + maltoheptaose
-
Thermus thermophilus HB8 / ATCC 27634 / DSM 579 ?
-
?
maltohexaose + maltohexaose
-
Thermus thermophilus ?
-
?
maltohexaose + maltohexaose
-
Thermus thermophilus HB8 / ATCC 27634 / DSM 579 ?
-
?
maltopentaose + maltopentaose
-
Thermus thermophilus ?
-
?
maltopentaose + maltopentaose
-
Thermus thermophilus HB8 / ATCC 27634 / DSM 579 ?
-
?
maltotetraose + maltotetraose
-
Thermus thermophilus ?
-
?
maltotriose + maltotriose
-
Thermus thermophilus glucose + maltooligosaccharides
-
?
additional information Thermus thermophilus AMase is among the most efficient 4-alpha-glucanotransferases in the alpha-amylase superfamily Thermus thermophilus ?
-
?
additional information substrates are maltooligomers, trimer to heptamer, substrate binding mechanism and structure, modeling. The active site contains at least seven substrate binding sites, subsites -2 and +3 favoring substrate binding and subsites -3 and +2 do not, substrate specificity, overview Thermus thermophilus ?
-
?
additional information Thermus thermophilus AMase is among the most efficient 4-alpha-glucanotransferases in the alpha-amylase superfamily Thermus thermophilus HB8 / ATCC 27634 / DSM 579 ?
-
?
additional information substrates are maltooligomers, trimer to heptamer, substrate binding mechanism and structure, modeling. The active site contains at least seven substrate binding sites, subsites -2 and +3 favoring substrate binding and subsites -3 and +2 do not, substrate specificity, overview Thermus thermophilus HB8 / ATCC 27634 / DSM 579 ?
-
?

Subunits

Subunits Comment Organism
? x * 59337, sequence calculation Thermus thermophilus

Synonyms

Synonyms Comment Organism
AMase
-
Thermus thermophilus
amylomaltase
-
Thermus thermophilus
More the enzyme belongs to the glycoside hydrolase family 77, GH77, which belongs to the alpha-amylase superfamily, Clan H, together with GH13 and GH70 Thermus thermophilus

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
70
-
assay at Thermus thermophilus

Temperature Range [°C]

Temperature Minimum [°C] Temperature Maximum [°C] Comment Organism
50 90
-
Thermus thermophilus

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
80
-
stable up to at pH 5.5, half-life is 18 min Thermus thermophilus

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.68
-
maltotriose pH 5.5, 70°C, mutant D249S Thermus thermophilus
0.97
-
maltotetraose pH 5.5, 70°C, mutant D249S Thermus thermophilus
1.99
-
maltoheptaose pH 5.5, 70°C, mutant D249S Thermus thermophilus
3.26
-
maltohexaose pH 5.5, 70°C, mutant D249S Thermus thermophilus
3.98
-
maltopentaose pH 5.5, 70°C, mutant D249S Thermus thermophilus
106
-
maltotetraose pH 5.5, 70°C, mutant F366L Thermus thermophilus
111
-
maltotriose pH 5.5, 70°C, mutant F366L Thermus thermophilus
159
-
maltoheptaose pH 5.5, 70°C, mutant F366L Thermus thermophilus
179
-
maltopentaose pH 5.5, 70°C, mutant F366L Thermus thermophilus
188
-
maltohexaose pH 5.5, 70°C, mutant F366L Thermus thermophilus
213
-
maltoheptaose pH 5.5, 70°C, wild-type enzyme Thermus thermophilus
304
-
maltohexaose pH 5.5, 70°C, wild-type enzyme Thermus thermophilus
317
-
maltotriose pH 5.5, 70°C, wild-type enzyme Thermus thermophilus
329
-
maltopentaose pH 5.5, 70°C, wild-type enzyme Thermus thermophilus
425
-
maltotetraose pH 5.5, 70°C, wild-type enzyme Thermus thermophilus

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
5.5
-
assay at Thermus thermophilus

pH Range

pH Minimum pH Maximum Comment Organism
4 7.5 pH dependence of wild-type and mutant enzymes, D293N and E340Q are active below pH 6.5 and pH 5.5, respectively, but precipitate during the necessary prolonged incubation times, wild-type Tt AMase precipitates below pH 5.5 under similar extended incubation times as well, overview Thermus thermophilus

pH Stability

pH Stability pH Stability Maximum Comment Organism
4 7.5 pH stability of wild-type and mutant enzymes, overview Thermus thermophilus

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.003
-
acarbose pH 5.5, 70°C, competitive inhibition Thermus thermophilus
0.004
-
acarbose pH 5.5, 70°C, uncompetitive inhibition Thermus thermophilus