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Literature summary for 3.2.1.1 extracted from

  • Yuk, J.B.; Choi, S.H.; Lee, T.H.; Jang, M.U.; Park, J.M.; Yi, A.R.; Svensson, B.; Kim, T.J.
    Effects of calcium ion concentration on starch hydrolysis of barley alpha-amylase isozymes (2008), J. Microbiol. Biotechnol., 18, 730-734.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
cloned and overexpressed in Pichia pastoris, recombinant isoenzymes with a six-histidine fusion tag Hordeum vulgare

Metals/Ions

Metals/Ions Comment Organism Structure
Ca2+ AMY1 shows the highest activity at 5 mM calcium concentration and maintains its activity at a broad range from 0.1 to 10 mM of calcium ion. AMY2 shows the highest acitivity at 15-20 mM of calcium, compared with the lowest 20% of activity at 0.1 mM of calcium concentration, 37°C, substrate insoluble blue starch. There is no significant difference in hydrolyzing activity on the soluble starch substrate between AMY1 and AMY2, with the increase of calcium concentration. The increase in calcium up to 50 mM causes the decrease by 0-30% in the activity of both AMYs Hordeum vulgare

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
45000
-
AMY1 or AMY2, SDS-PAGE Hordeum vulgare

Organism

Organism UniProt Comment Textmining
Hordeum vulgare
-
-
-

Purification (Commentary)

Purification (Comment) Organism
recombinant enzyme Hordeum vulgare

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
additional information
-
AMY1 with various substrates: 25.74 U/mg with insoluble blue starch, 132.64 U/mg with corn starch, 189.31 U/mg with potato starch, 153.28 U/mg with soluble starch (Showa Chemical Co.), and 296.6 U/mg with soluble starch (Sigma-Aldrich). AMY2 with various substrates: 17.64 U/mg with insoluble blue starch, 131.71 U/mg with corn starch, 222.34 U/mg with potato starch, 272.68 U/mg with soluble starch (Showa Chemical Co.), and 210.24 U/mg with soluble starch (Sigma-Aldrich) Hordeum vulgare

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
maltoheptaose + H2O
-
Hordeum vulgare maltotriose + maltose + D-glucose identified by thin-layer-chromatography ?
maltohexaose + H2O
-
Hordeum vulgare maltotetraose + maltotriose + maltose + D-glucose identified by thin-layer-chromatography ?
maltopentaose + H2O
-
Hordeum vulgare maltotetraose + maltotriose + maltose + D-glucose identified by thin-layer-chromatography ?
maltotetraose + H2O
-
Hordeum vulgare maltotriose + maltose identified by thin-layer-chromatography ?
maltotriose + H2O
-
Hordeum vulgare maltose + D-glucose identified by thin-layer-chromatography ?
starch + H2O
-
Hordeum vulgare ?
-
?

Subunits

Subunits Comment Organism
? x * 45000, AMY1 or AMY2, SDS-PAGE Hordeum vulgare

Synonyms

Synonyms Comment Organism
AMY1 isoenzyme Hordeum vulgare
AMY2 isoenzyme Hordeum vulgare

pH Stability

pH Stability pH Stability Maximum Comment Organism
3.5
-
AMY1 is more stable at low pH than AMY2. The activity of AMY2 rapidly decreases to 51% after 3 min incubation at pH 3.5 Hordeum vulgare