Literature summary for 3.2.1.1 extracted from

Sai Kumar, R.S.; Singh, S.A.; Rao, A.G.
Conformational stability of alpha-amylase from malted sorghum (Sorghum bicolor): reversible unfolding by denaturants (2009), Biochimie, 91, 548-557.

Molecular Weight [Da]

Molecular Weight [Da]	Molecular Weight Maximum [Da]	Comment	Organism
47000	-	SDS-PAGE	Sorghum bicolor

Organism

Organism	UniProt	Comment	Textmining
Sorghum bicolor	-	var. M25-1	-

Purification (Commentary)

Purification (Comment)	Organism
seeds of Sorghum bicolor	Sorghum bicolor

Renatured (Commentary)

Renatured (Comment)	Organism
the enzyme can be unfolded completely by incubating for 4 h with 4 M guanidine HCl or for 12 h with 8 M urea in 0.05 M acetate buffer, pH 4.8, 13.6. mM Ca2+. 0.05 M HEPES buffer, pH 7.0 with 13.6 mM Ca2+ required incubation with 5 M guanidine HCl for 4 h to completely unfold the enzyme. The enzyme refolds on diluting 25 times with HEPES buffer containing 15 mM dithiothreitol, resulting in the recovery of ca. 85% of the activity. The refolded enzyme regains secondary and tertiary structure similar to the native enzyme. Refolding experiments with the acetate buffer do not yield active enzyme. alpha-Amlyase is more resistant to unfolding at pH 7.0 in comparison to unfolding at pH 4.8. The enzyme shows significant unfolding at 27°C, at urea concentrations below 9 M, pH 7.0	Sorghum bicolor

Renatured (Comment)

Organism

the enzyme can be unfolded completely by incubating for 4 h with 4 M guanidine HCl or for 12 h with 8 M urea in 0.05 M acetate buffer, pH 4.8, 13.6. mM Ca2+. 0.05 M HEPES buffer, pH 7.0 with 13.6 mM Ca2+ required incubation with 5 M guanidine HCl for 4 h to completely unfold the enzyme. The enzyme refolds on diluting 25 times with HEPES buffer containing 15 mM dithiothreitol, resulting in the recovery of ca. 85% of the activity. The refolded enzyme regains secondary and tertiary structure similar to the native enzyme. Refolding experiments with the acetate buffer do not yield active enzyme. alpha-Amlyase is more resistant to unfolding at pH 7.0 in comparison to unfolding at pH 4.8. The enzyme shows significant unfolding at 27°C, at urea concentrations below 9 M, pH 7.0

Sorghum bicolor

Source Tissue

Source Tissue	Comment	Organism	Textmining
seed	-	Sorghum bicolor	-

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg]	Specific Activity Maximum [µmol/min/mg]	Comment	Organism
additional information	-	25000 U/mg, pH 7.0, 27°C	Sorghum bicolor

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
soluble starch + H2O	-	Sorghum bicolor	alpha-maltose + ?	-	?

Subunits

Subunits	Comment	Organism
?	x * 47000, SDS-PAGE	Sorghum bicolor

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
27	-	assay at	Sorghum bicolor

Temperature Stability [°C]

Temperature Stability Minimum [°C]	Temperature Stability Maximum [°C]	Comment	Organism
25	85	alpha-amylase do not unfold at pH 7.0 in the temperature range of 25-85°C, it unfolds at pH 4.8. Guanidine HCl is more effective than urea. Thermal unfolding is irreversible for Sorghum alpha-amylase	Sorghum bicolor

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
4.8	-	-	Sorghum bicolor

pH Stability

pH Stability	pH Stability Maximum	Comment	Organism
4.8	8	over 90% of the secondary and tertiary structural elements are retained, indicating unfolding of the enzyme under both acidic and basic pH conditions. The enzyme retains its native conformation. The enzyme is found to be unfolded with loss of both structure and activity at pH below 3.0 and above 10.0	Sorghum bicolor
7	-	maximal stability for structure as well as activity at pH 7.0	Sorghum bicolor