Amylase is hypothesized to involve in the initiation of intracellular starch granule digestion in the plastids of ripening durians. A putative α-amylase from Mon Thong durian (Durio zibethinus Murr. cv. Mon Thong; DzAmy3) was successfully isolated and its gene contain a 2,679 base pair open reading frame, which encodes 892 amino acids with a calculated molecular mass of 93.7 kDa and an isoelectric point of 5.77. The DzAmy3 contains starch binding domain with a putative plastid transit peptide and α-amylase like domain. Phylogenetic tree analysis proved it into the family three of plant α-amylases. The predicted structural model proposed a catalytic triad (Asp611, Glu636 and Asp719) for general acid/base hydrolysis. Recombinant DzAmy3 (rDzAmy3) was successfully expressed in Escherichia coli. rDzAmy3 hydrolyzed starch and ethylidene-pNP-G7 which confirms the authenticity of DzAmy3 gene and functional α-amylase. The rDzAmy3 had an optimum activity at pH 8.0 and 30°C. It was stable in the pH range of 7-8 at 37°C, temperature range of 5-20°C and in the presence of 1% (v/v) Tween 20 and Triton X-100. Substrate specificity analysis revealed that rDzAmy3 was active toward β-limit dextrin, starch, amylopectin, amylose and glycogen.

Abstract:The 594-amino acid residue sequence of α-amylase, MiAmy, from the Ok-rong mango (Mangifera indica Linn. cv. Ok-rong), in the ripening stage, was determined through Reverse Transcription Polymerase Chain Reaction (RT-PCR). Sequence alignments and evolutionary tree analyses revealed its high similarity to plastid α-amylase from many other plants. The sequence was revealed to have four conserved regions with catalytic amino acid residues for the active site. It was classified as a member of α-amylase family 13 because it has an active Domain A, similar to a (β/α) 8 -barrel structure. Three-dimensional structural predictions revealed that this partial sequence completely covered all of necessary domains for amylase activity.

Khao-Mao producer group in Thailand’s Nakhon Phanom province’s Phon Sawan district, Na Hua Bo sub-district is a community that has produced Khao-Mao according to conventional wisdom, for a very long time. Khao-Mao has an emerald, green color, fragrant, delicate texture, and delicious taste, however the essential nutritional facts are not provided. Consequently, this study’s goal was to evaluate nutritional values by proximate analysis. All 6 types of young flattened rice-: Laos Wan, Kor Khor 6(RD6), Ai Lueng, San Pa Tong, Yee Pun, and Hom Nang Nuan have phenolic compounds by Folin-Ciocalteu method and antioxidant properties by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. According to the findings, rice's primary constituents are carbohydrates, which range from 69.76 to 73.07 %, protein, which ranges from 4.79 to 6.11 %, crude fat, which ranges from 1.68 to 2.22 %, fiber, which ranges from 0.00 to 0.03 % moisture, which ranges from 17.96 to 21.31 %, and ash, which ranges from 1.13 to 1.70 %. The San Pa Tong Khao-Mao has the highest 6.11% of protein content. Ai Lueng Khao-Mao has the greatest levels of total phenolic compounds, 0.79 mg/g dry weight. The DPPH radical scavenging assay test was used to measure the antioxidant activity. Their half-maximal inhibitory concentration (IC50) value falls between 1.18 and 2.00 mg/mL. The Hom Nang Nuan Khao-Mao has the lowest 1.18 mg/mL of IC50. According to the study’s findings, this community’s Khao-Mao has good nutritional and antioxidant properties. HIGHLIGHTS Khao-Mao has high proximate composition and high energy value Khao-Mao has relatively high quantities of protein and phenolic compounds Khao-Mao is a dish with a high-level antioxidant activity GRAPHICAL ABSTRACT

The thermostable α-amylase from germinating sword bean (Canavalia gladiata (Jacq.) DC.) seeds (CgAmy) was successfully purified by a combination of ammonium sulphate fractionation and Epoxy-activated Sepharose 6B affinity chromatography. The purified α-amylase showed 507.8 fold with a specific activity of 750.0 U/mg. SDS-PAGE of the purified enzyme revealed a single protein band of 50.0 kDa. Purified enzyme was confirmed as α-amylase type by LC-MS/MS analysis and activity on specific substrate of ethylidene-pNP-G7. The CgAmy revealed extreme activity at a high temperature of 50.0-70.0°C with optimum activity at 70.0°C. The optimal pH of enzyme activity was observed at 6.0. The CgAmy exhibited stability in pH range of 5.0-8.0 and highly thermostable with a temperature of 40.0-60.0°C. The kinetic parameters K m for hydrolysis of starch were found to be 3.12 mg/ml. The α-amylase activity was enhanced in the presence of Co 2+ and β-mercaptoethanol. While, Na 2+ , K 2+ , Ca 2+ , Mg 2+ , Zn 2+ , Ba 2+ , Fe 2+ and Cd 2+ slightly inhibited α-amylase activity. Interestingly, the CgAmy displayed stability towards some organic solvents and detergents. Stability at high temperature and some metal ions, organic solvents and detergents indicated that this enzyme has potential for various applications.

The secreted α-amylase with dominant activity was purified from the crude extract of Mon Thong durian by steps of ammonium sulphate precipitation and the affinity column chromatography. The purified α-amylase (DzAmy1) had a molecular mass of approximately 44 kDa. Its optimum pH and temperature for activity were 7.0 and 50°C, respectively. The enzyme was stable from pH 6 to 10 and from 30 to 60°C. Many metal ions did not affect amylase activity. The gene cloning of DzAmy1 was carried out and it was confirmed that DzAmy1 gene consisted of 1,254 bp open reading frame, which encoded 23 amino acids of the signal peptide and 395 amino acids of mature protein with a calculated molecular mass of 43.7 kDa. The isoelectric point of the enzyme was 5.78. DzAmy1 was shown to belong to sub-family one of the plant α-amylases based on phylogenetic tree analysis. Structural characterization by homology modelling suggested that it consisted of 3 domains with a catalytic triad in domain A. Recombinant DzAmy1 (rDzAmy1) was successfully expressed in Escherichia coli and had hydrolysis activity for starch and ethylidene-pNP-G7, which was clearly confirmed the authenticity of DzAmy1 as a functional α-amylase.