Comparative studies of two α-amylases acting on two Sorghum hybrids starches (Montecillos hybrid 2 and 3) and their significant differences in their catalytic activities

Suárez-Diéguez, Teodoro; Soriano-Garcı́a, Manuel; Anaya-Sosa, I.; Victoria, María

doi:10.1016/j.carbpol.2008.09.015

Cited by 9 publications

(2 citation statements)

References 10 publications

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“…D206, E230, and D297 (shown in sticks) in the binding site interacted with ligand. These residues coincided with the proposed catalytic triad of α-amylase in experimental and simulation studies [ 29 , 47 – 48 ]. It was clearly seen that the binding site of maltotriose concerning AmyB exposed more polar contact number with ligand than AmyA ( Fig 5 ).…”

Section: Resultssupporting

confidence: 78%

Aspergillus Oryzae S2 α-Amylase Domain C Involvement in Activity and Specificity: In Vivo Proteolysis, Molecular and Docking Studies

et al. 2016

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We previously reported that Aspergillus oryzae strain S2 had produced two α-amylase isoforms named AmyA and AmyB. The apparent molecular masses revealed by SDS-PAGE were 50 and 42 kDa, respectively. Yet AmyB has a higher catalytic efficiency. Based on a monitoring study of the α-amylase production in both the presence and absence of different protease inhibitors, a chymotrypsin proteolysis process was detected in vivo generating AmyB. A. oryzae S2 α-amylase gene was amplified, cloned and sequenced. The sequence analysis revealed nine exons, eight introns and an encoding open reading frame of 1500 bp corresponding to AmyA isoform. The amino-acid sequence analysis revealed aY371 potential chymotrypsin cleaving site, likely to be the AmyB C-Terminal end and two other potential sites at Y359, and F379. A zymogram with a high acrylamide concentration was used. It highlighted two other closed apparent molecular mass α-amylases termed AmyB1 and AmyB2 reaching40 kDa and 43 kDa. These isoforms could be possibly generated fromY359, and F379secondary cut, respectively. The molecular modeling study showed that AmyB preserved the (β/α)8 barrel domain and the domain B but lacked the C-terminal domain C. The contact map analysis and the docking studies strongly suggested a higher activity and substrate binding affinity for AmyB than AmyA which was previously experimentally exhibited. This could be explained by the easy catalytic cleft accessibility.

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Section: Resultssupporting

confidence: 78%

Aspergillus Oryzae S2 α-Amylase Domain C Involvement in Activity and Specificity: In Vivo Proteolysis, Molecular and Docking Studies

et al. 2016

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“…The effect of pH on the rate of hydrolysis of both sorghum (Montecillo 2 and 3) hybrids starches by IBA and AOA have been reported [26]. The curves shows an optimum pH's for the fungal and bacterial amylases between 5.5-6.0 and 6.0-7.0, respectively.…”

Section: Activities For Iba and Aoamentioning

confidence: 97%

Electrostatics at the Active Site of Two α-Amylases: Direct Comparison of Experiment with Theory

M¹,

Victoria²

2018

JAPLR

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The vital importance of electrostatics in catalysis has been emphasized in the literature for a large number of enzymes. The effect of pH on the rate of hydrolysis of both sorghum (Montecillo 2 and 3) hybrids starches by industrial bacterial amylase (IBA) and Aspergillus oryzae α-amylase (AOA) was studied. This result suggests that among the two amylases compared, both IBA and AOA α-amylases had slightly high affinity for soluble starch of sorghum Montecillo 3 and 1 hybrids, respectively. We examined the differences in the pH-activity profiles for the industrial bacterial amylase (IBA) and Aspergillus oryzae α-amylase (AOA) acting on both sorghum (Montecillo 2 and 3) hybrids starches which show a real change in the net charge on the active site. Both our experimental data and prediction studies indicated that the average pKa values are in good agreement with the predicted values of 5.44 and 6.59. Keywords:

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Biocatalytic Aza‐Michael Addition of Aromatic Amines to Enone Using α‐Amylase in Water

et al. 2019

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The Michael addition of amines with enones for synthesizing β‐amino carbonyls constitutes a valuable transformation in organic chemistry. While various catalyst have been made available for catalyzing the Michael addition of aromatic amines to enones but there is no report of using α‐amylase enzyme to catalyze this transformation. The α‐amylase from Aspergillus oryzae was found to catalyze the Michael addition of various aryl (hetero) amines to methyl vinyl ketone with high catalytic efficiency (63–83% yield). A hybrid of α‐amylase with copper nanoparticle (α‐amylase@CuNPs) has been prepared and used to catalyze this transformation as a reusable catalyst. Further, an application of α‐amylase catalyzed aza‐Michael addition in the cascade reactions has been exhibited by synthesizing biologically important 3‐acetyl quinoline. In addition, molecular docking and molecular dynamics (MD) simulation studies are carried out to get insight into the key interactions of the substrates with the amino acid residues near the active site and the probable reaction mechanism, which reveals Glu230 and Asn295 play a crucial role in the substrate activation process.

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Comparative studies of two α-amylases acting on two Sorghum hybrids starches (Montecillos hybrid 2 and 3) and their significant differences in their catalytic activities

Cited by 9 publications

References 10 publications

Aspergillus Oryzae S2 α-Amylase Domain C Involvement in Activity and Specificity: In Vivo Proteolysis, Molecular and Docking Studies

Aspergillus Oryzae S2 α-Amylase Domain C Involvement in Activity and Specificity: In Vivo Proteolysis, Molecular and Docking Studies

Electrostatics at the Active Site of Two α-Amylases: Direct Comparison of Experiment with Theory

Biocatalytic Aza‐Michael Addition of Aromatic Amines to Enone Using α‐Amylase in Water

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