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Literature summary for 3.2.1.2 extracted from

  • Yoshigi, N.; Okada, Y.; Maeba, H.; Sahara, H.; Tamaki, T.
    Construction of a plasmid used for the expression of a sevenfold-mutant barley beta-amylase with increased thermostability in Escherichia coli and properties of the sevenfold-mutant beta-amylase (1995), J. Biochem., 118, 562-567.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
expression of a sevenfold mutant beta-amylase, M185L/S295A/I297V/S350P/S351P/Q352D/A376S Hordeum vulgare

Protein Variants

Protein Variants Comment Organism
M185L/S295A/I297V/S350P/S351P/Q352D/A376S the mutant enzyme acquires enhanced thermostability, but its function as beta-amylase is unchanged. The mutant is stable at pH-values up to 12.5, while the original recombinant enzyme is unstable at pH-values above pH 9.5 Hordeum vulgare

Inhibitors

Inhibitors Comment Organism Structure
Ag+ 1 mM, almost complete inhibition of mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S Hordeum vulgare
Cd2+ 1 mM, almost complete inhibition of barley enzyme and recombinant enzyme, less inhibitory towards mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S Hordeum vulgare
Cu2+ 1 mM, almost complete inhibition of mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S Hordeum vulgare
Hg2+ 1 mM, almost complete inhibition of mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S Hordeum vulgare
PCMB
-
Glycine max
PCMB 0.1 mM, complete inhibition of mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S Hordeum vulgare
Zn2+ 1 mM, almost complete inhibition of barley enzyme and recombinant enzyme, less inhibitory towards mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S Hordeum vulgare

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.491
-
amylose DP = 17, mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S Hordeum vulgare
1.83
-
maltoheptaose mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S Hordeum vulgare
2
-
maltohexaose mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S Hordeum vulgare
2.83
-
maltopentaose mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S Hordeum vulgare
4.17
-
maltotetraose mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S Hordeum vulgare

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
56000
-
x * 56000, mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S, SDS-PAGE Hordeum vulgare
59144
-
x * 59144, mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S, calculation from amino acid sequence Hordeum vulgare

Organism

Organism UniProt Comment Textmining
Glycine max
-
-
-
Hordeum vulgare
-
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
amylopectin + H2O
-
Hordeum vulgare beta-maltose + ?
-
?
amylopectin + H2O
-
Glycine max beta-maltose + ?
-
?
amylose + H2O DP = 17 Hordeum vulgare beta-maltose
-
?
glycogen + H2O from oyster Hordeum vulgare beta-maltose
-
?
maltoheptaose + H2O
-
Hordeum vulgare ?
-
?
maltohexaose + H2O
-
Hordeum vulgare ?
-
?
maltopentaose + H2O
-
Hordeum vulgare ?
-
?
maltotetraose + H2O
-
Hordeum vulgare ?
-
?
starch + H2O soluble Hordeum vulgare maltose + ?
-
?
starch + H2O soluble Glycine max maltose + ?
-
?

Subunits

Subunits Comment Organism
?
-
Glycine max
? x * 59144, mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S, calculation from amino acid sequence Hordeum vulgare
? x * 56000, mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S, SDS-PAGE Hordeum vulgare

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
55
-
original and recombinant enzyme Hordeum vulgare
60
-
-
Glycine max
65
-
mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S Hordeum vulgare

Temperature Stability [°C]

Temperature Stability Minimum [°C] Temperature Stability Maximum [°C] Comment Organism
57
-
30 min, 50% loss of activity Hordeum vulgare
57
-
30 min, recombinant enzyme, 50% loss of activity Hordeum vulgare
63
-
30 min, 50% loss of activity Glycine max
69
-
30 min, mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S, 50% inactivation Hordeum vulgare

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
5
-
-
Hordeum vulgare

pH Stability

pH Stability pH Stability Maximum Comment Organism
9.5
-
unstable above, original recombinant enzyme Hordeum vulgare
12.5
-
mutant enzyme M185L/S295A/I297V/S350P/S351P/Q352D/A376S is stable up to Hordeum vulgare