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Literature summary extracted from

  • Ragunath, C.; Manuel, S.G.; Venkataraman, V.; Sait, H.B.; Kasinathan, C.; Ramasubbu, N.
    Probing the role of aromatic residues at the secondary saccharide-binding sites of human salivary alpha-amylase in substrate hydrolysis and bacterial binding (2008), J. Mol. Biol., 384, 1232-1248.
    View publication on PubMedView publication on EuropePMC

Crystallization (Commentary)

EC Number Crystallization (Comment) Organism
3.2.1.1 HSAmy and HSAmy-ar both show characteristics of a protein with ordered secondary structures, suggesting that the overall conformation of HSamy still retains in the mutant HSAmy-ar. Single or double mutations also do not alter the overall conformation of the enzyme Homo sapiens

Protein Variants

EC Number Protein Variants Comment Organism
3.2.1.1 W134A/W203A/Y276A/W284A/W316A/W388A HSAmy-ar, multiple mutant, 10fold reduction of activity compared with wild-type enzyme and also sigificant reductaion of starch binding activity Homo sapiens
3.2.1.1 W203A 2fold reduction of activity compared to the wild-type enzyme, similar starch-binding activity like the wild-type enzyme Homo sapiens
3.2.1.1 W284A similar specific activity and similar starch-binding activity like the wild-type enzyme Homo sapiens
3.2.1.1 W316A/W388A similar specific activity and similar starch-binding activity like the wild-type enzyme Homo sapiens
3.2.1.1 Y276/W284A similar specific activity and similar starch-binding activity like the wild-type enzyme Homo sapiens
3.2.1.1 Y276A similar specific activity and similar starch-binding activity like the wild-type enzyme Homo sapiens

Organism

EC Number Organism UniProt Comment Textmining
3.2.1.1 Homo sapiens P04745
-
-

Source Tissue

EC Number Source Tissue Comment Organism Textmining
3.2.1.1 saliva
-
 Homo sapiens
-

Specific Activity [micromol/min/mg]

EC Number Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
3.2.1.1 additional information
-
 the specific activity of the mutant HSAmy-ar decreases by 87% (a 10fold reduction) compared to the wild-type HSAmy, indicating that the absence of saccharide-binding ability at the secondary binding sites in HSAmy-ar has resulted in a significant reduction in enzyme activity. The activity is also affected by about 2fold when the aromatic residue at position 203 is mutated. Among the single or douible mutants studied, W203A exhibit the least activity against starch hydrolsis. The mutation at position W284 do not alter the specific activity to any significant extent. Double mutations at the residues W316 and E388 also do not affect activity Homo sapiens

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
3.2.1.1 maltoheptaoside + H2O all mutants possess the ability to hydrolyze heptasaccharide substrates and generate a similar product profile like the wild-type enzyme. The three mutants W203A, W284A, HSAmy-ar generate less products. They require higher enzyme concentration (600 nM vs. 60 nM for HSAmy and the other mutants) and more time (5 min vs. 2 min) 25°C, pH 6.9 Homo sapiens ?
-
 ?
3.2.1.1 maltopentaoside + H2O all mutants possess the ability to hydrolyze pentasaccharide substrates and generate a similar product profile like the wild-type enzyme. The three mutants W203A, W284A, HSAmy-ar generate less products. They require higher enzyme concentration (600 nM vs. 60 nM for HSAmy and the other mutants) and more time (5 min vs. 2 min) 25°C, pH 6.9 Homo sapiens ?
-
 ?
3.2.1.1 starch + H2O 25°C, pH 6.9 Homo sapiens ?
-
 ?

Synonyms

EC Number Synonyms Comment Organism
3.2.1.1 HSAmy
-
 Homo sapiens
3.2.1.1 HSAmy-ar multiple mutant enzyme Homo sapiens

Temperature Optimum [°C]

EC Number Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
3.2.1.1 25
-
 assay at Homo sapiens

pH Optimum

EC Number pH Optimum Minimum pH Optimum Maximum Comment Organism
3.2.1.1 6.9
-
 assay at Homo sapiens