Papers by Piamsook Pongsawasdi
Molecules, 2022
Amylomaltase is a well-known glucan transferase that can produce large ring cyclodextrins (LR-CDs... more Amylomaltase is a well-known glucan transferase that can produce large ring cyclodextrins (LR-CDs) or so-called cycloamyloses via cyclization reaction. Amylomaltases have been found in several microorganisms and their optimum temperatures are generally around 60–70 °C for thermostable amylomaltases and 30–45 °C for the enzymes from mesophilic bacteria and plants. The optimum pHs for mesophilic amylomaltases are around pH 6.0–7.0, while the thermostable amylomaltases are generally active at more acidic conditions. Size of LR-CDs depends on the source of amylomaltases and the reaction conditions including pH, temperature, incubation time, and substrate. For example, in the case of amylomaltase from Corynebacterium glutamicum, LR-CD productions at alkaline pH or at a long incubation time favored products with a low degree of polymerization. In this review, we explore the synthesis of LR-CDs by amylomaltases, structural information of amylomaltases, as well as current applications of LR...
World Journal of Microbiology and Biotechnology
Acta Crystallographica Section D Structural Biology
α-Glucosidase (EC 3.2.1.20) is a carbohydrate-hydrolyzing enzyme which generally cleaves α-1,4-gl... more α-Glucosidase (EC 3.2.1.20) is a carbohydrate-hydrolyzing enzyme which generally cleaves α-1,4-glycosidic bonds of oligosaccharides and starch from the nonreducing ends. In this study, the novel α-glucosidase from Weissella cibaria BBK-1 (WcAG) was biochemically and structurally characterized. WcAG belongs to glycoside hydrolase family 13 (GH13) and to the neopullanase subfamily. It exhibits distinct hydrolytic activity towards the α-1,4 linkages of short-chain oligosaccharides from the reducing end. The enzyme prefers to hydrolyse maltotriose and acarbose, while it cannot hydrolyse cyclic oligosaccharides and polysaccharides. In addition, WcAG can cleave pullulan hydrolysates and strongly exhibits transglycosylation activity in the presence of maltose. Size-exclusion chromatography and X-ray crystal structures revealed that WcAG forms a homodimer in which the N-terminal domain of one monomer is orientated in proximity to the catalytic domain of another, creating the substrate-bindi...
Journal of Applied Microbiology
To express amylomaltase from Thermus filiformis (TfAM) in a generally recognized as safe (GRAS) o... more To express amylomaltase from Thermus filiformis (TfAM) in a generally recognized as safe (GRAS) organism and to use the enzyme in starch modification.
The purified IgG fraction of anti-CGTase was coupled to CNBr-activated Sepharose 4B and used as i... more The purified IgG fraction of anti-CGTase was coupled to CNBr-activated Sepharose 4B and used as immunoaffinity gel to purify CGTase from Bacillus circulans A11. The enzyme was successfully purified to approximately 155 folds with a 45% yield and specific activity of 3302 units/mg protein. It was a single polypeptide of 72 KDa. The amino acid composition of this CGTase was found to contain high amounts of Asx, Glx, Gly, Ala, and Thr and low amounts of His, Met, Cys, and Trp. N-Terminal sequence was A P D T S V S N K Q N F S T D V I Y Q I. Chemical modification and substrate protection studies indicate the presence of Trp, His, Tyr, and Asx/Glx residues at the active site of CGTase, while Cys, Lys, and Ser were proved to have no influence on CGTase catalysis. From HPLC analysis of products of enzymatic reaction, this CGTase produced mainly β-CD. The ratio of α : β : γ -CD was 1 : 4.1 : 1.1. When analyzed by non-denaturing PAGE, the enzyme demonstrates the isoform pattern. Four isoform...
Biochemical and Biophysical Research Communications, 2016
Amylomaltase catalyzes intermolecular and intramolecular transglucosylation reactions to form lin... more Amylomaltase catalyzes intermolecular and intramolecular transglucosylation reactions to form linear and cyclic oligosaccharides, respectively. The aim of this work is to investigate the structure-function relationship of amylomaltase from a mesophilic Corynebacterium glutamicum (CgAM). Site-directed mutagenesis was performed to substitute Tyr for Asn287 (N287Y) to determine its role in controlling amylomaltase activity and product formation. Expression of the wild-type (WT) and N287Y was achieved by cultivating recombinant cells in the medium containing lactose at 16 °C for 14 h. The purified mutated enzyme showed a significant decrease in all transglucosylation activities while hydrolysis activity was not changed. Optimum temperature and pH for disproportionation reaction were slightly changed upon mutation while those for cyclization reaction were not changed. Interestingly, N287Y showed a change in large-ring cyclodextrin (LR-CD) product profile in which the larger size was observed together with an increase in thermostability and substrate preference for G5 in addition to G3. The secondary structure of the mutated enzyme was slightly changed in related to the WT as evidenced from circular dichroism analysis. This work thus demonstrates that N287 is required for transglucosylation activities of CgAM. Having an aromatic residue in this position increased thermostability, changed product profile and substrate preference but demolished most enzyme activities.
Journal of Biochemistry and …, 2004
The expression of the Paenibacillus sp. A11 cyclodextrinase (CDase) gene using the pUC 18 vector ... more The expression of the Paenibacillus sp. A11 cyclodextrinase (CDase) gene using the pUC 18 vector in Escherichia coli JM 109 resulted in the formation of an insoluble CDase protein in the cell debris in addition to a soluble CDase protein in the cytoplasm. Unlike the expression in Paenibacillus sp. A11, CDase was primarily observed in cytoplasm. However, by adding 0.5 M sorbitol as an osmolyte, the formation of insoluble CDase was prevented while a threefold increase in cytoplasmic CDase activity was achieved after a 24 h-induction. The recombinant CDase protein was purified to approximately 14-fold with a 31% recovery to a specific activity of 141 units/mg protein by 40-60% ammonium sulfate precipitation, DEAE-Toyopearl 650 M, and Phenyl Sepharose CL-4B chromatography. It was homogeneous by non-denaturing and SDS-PAGE. The enzyme was a single polypeptide with a molecular weight of 80 kDa, as determined by gel filtration and SDS-PAGE. It showed the highest activity at pH 7.0 and 40 o C. The catalytic efficiency (k cat /K m) values for α-, β-, and γ-CD were 3.0 × 10 5 , 8.8 × 10 5 , and 5.5 × 10 5 M −1 min-1 , respectively. The enzyme hydrolyzed CDs and linear maltooligosaccharides to yield maltose and glucose with less amounts of maltotriose and maltotetraose. The rates of hydrolysis for polysaccharides, soluble starch, and pullulan were very low. The cloned CDase was strongly inactivated by N-bromosuccinimide and diethylpyrocarbonate, but activated by dithiothreitol. A comparison of the biochemical properties of the CDases from Paenibacillus sp. A11 and E. coli transformant (pJK 555) indicates that they were almost identical.
Scientific Reports
Amylomaltase (AM) catalyzes transglycosylation of starch to form linear or cyclic oligosaccharide... more Amylomaltase (AM) catalyzes transglycosylation of starch to form linear or cyclic oligosaccharides with potential applications in biotechnology and industry. In the present work, a novel AM from the mesophilic bacterium Streptococcus agalactiae (SaAM), with 18–49% sequence identity to previously reported AMs, was characterized. Cyclization and disproportionation activities were observed with the optimum temperature of 30 °C and 40 °C, respectively. Structural determination of SaAM, the first crystal structure of small AMs from the mesophiles, revealed a glycosyl-enzyme intermediate derived from acarbose and a second acarbose molecule attacking the intermediate. This pre-transglycosylation conformation has never been before observed in AMs. Structural analysis suggests that thermostability in AMs might be mainly caused by an increase in salt bridges since SaAM has a lower number of salt bridges compared with AMs from the thermophiles. Increase in thermostability by mutation was perfo...
Archives of Biochemistry and Biophysics
Monatshefte für Chemie - Chemical Monthly
Bulletin of Applied Glycoscience
Journal of Molecular Liquids
ScienceAsia
The new Editorial team has taken over the operation of ScienceAsia since February 2019, beginning... more The new Editorial team has taken over the operation of ScienceAsia since February 2019, beginning with Volume 45 Issue 1. We have reorganized ScienceAsia to achieve good and efficient management, so that now the Editorial team consists of the Editor-in-Chief, Editors and Managing Editor, as well as the Editorial Board. The Advisory Committee comprising former Presidents of the Science Society of Thailand and a former ScienceAsia Editor, will play an important role in giving advice on policy and administrative aspects of the journal. Our Editorial Board consists of renowned researchers specialized in different fields of sciences from within and outside Thailand, who will help raise ScienceAsia to a high standard with international reputation. We have classified the manuscripts in ScienceAsia into four sections (please see Journal policy for details), namely Biological Sciences and Biotechnology, Chemistry and Material Sciences, Environmental and Applied Sciences, and Mathematics and Physical Sciences. Balancing the content between sections in each issue will be our goal in order to serve readers in wide areas of science. However, please be informed that manuscripts in Social Science and Technologies are not in our focus. At this stage, we welcome research articles and short communications as defined in Instructions to Authors, while review articles will be by invitation only. A high proportion of manuscripts currently come from overseas, especially from the Asian region, but we would like to receive a good proportion of manuscripts from Thai authors, since the costs of the journal are partially supported by the Thai government through the National Research Council of Thailand. In this regard, please be aware that ScienceAsia has a publication charge (see details under Publication Charge) to help alleviate the costs of publication in both hard copy and electronic version. The most difficult task we confront is to speed up the handling process for submitted manuscripts. We will try our best to shorten this period through the work of the Editorial team, Editorial Board and Reviewers who are experts in various fields. Another point of concern is to push forward to increase the impact factor and quartile level of the journal, which can be achieved by publishing high quality manuscripts submitted by renowned scientists worldwide. In our new move, we also would like to ask the authors to take responsibility of preparing their manuscripts to meet the highest academic standards, with flawless language, precise referencing, and perfect formatting. Manuscripts with excellent English will help improve the quality of articles thereby enhancing the reputation of the journal. In case the submitted manuscript requires English language editing, the authors will be asked to use professional academic proofreading and editing services at their own expense before the manuscript is accepted. To help the authors, the list of professional proofreading services will be provided. On returning the manuscript to our online system, the authors must attach the certificate/ letter of proof issued by the service company. At this moment of the new transition of the editorial team, may I convey sincere appreciation from ScienceAsia to our authors, readers and reviewers for supporting the journal. The Advisory Committee, Editors and Editorial Board from the past to present are all deeply acknowledged. All your contributions have undoubtedly driven ScienceAsia to be on the move.
Scientia pharmaceutica, Jan 30, 2018
Pinostrobin (PNS) belongs to the flavanone subclass of flavonoids which shows several biological ... more Pinostrobin (PNS) belongs to the flavanone subclass of flavonoids which shows several biological activities such as anti-inflammatory, anti-cancerogenic, anti-viral and anti-oxidative effects. Similar to other flavonoids, PNS has a quite low water solubility. The purpose of this work is to improve the solubility and the biological activities of PNS by forming inclusion complexes with β-cyclodextrin (βCD) and its derivatives, heptakis-(2,6-di--methyl)-β-cyclodextrin (2,6-DMβCD) and (2-hydroxypropyl)-β-cyclodextrin (HPβCD). The A-type diagram of the phase solubility studies of PNS exhibited the formed inclusion complexes with the 1:1 molar ratio. Inclusion complexes were prepared by the freeze-drying method and were characterized by differential scanning calorimetry (DSC). Two-dimensional nuclear magnetic resonance (2D-NMR) and steered molecular dynamics (SMD) simulation revealed two different binding modes of PNS, i.e., its phenyl- (-PNS) and chromone- (-PNS) rings preferably inserte...
Biochemical and Biophysical Research Communications
Acta Crystallographica Section F Structural Biology and Crystallization Communications, Sep 1, 2013
Enzyme and Microbial Technology, Feb 1, 2005
Journal of food science, Jan 22, 2016
Amylomaltase (α-1,4-glucanotransferase, AM; EC 2.4.1.25) from Corynebacterium glutamicum expresse... more Amylomaltase (α-1,4-glucanotransferase, AM; EC 2.4.1.25) from Corynebacterium glutamicum expressed in Escherichia coli was used to prepare the enzyme-modified cassava starch for food application. About 5% to 15% (w/v) of cassava starch slurries were incubated with 1, 3, or 5 units of amylomaltase/g starch. Apparent amylose, amylopectin chain length distribution, thermal properties, freeze-thaw stability, thermo-reversibility, and gel strength of the obtained modified starches were measured. The apparent amylose content and retrogradation enthalpy were lower, whereas the retrogradation temperatures, freeze-thaw stability, and thermo-reversibility were higher than those of the native cassava starch. However, when amylomaltase content was increased to 20 units of amylomaltase/g starch and for 24 h, the modified starch showed an improvement in the thermo-reversibility property. When used in panna cotta, the gel strength of the sample using the 20 units/24 h modified cassava starch was s...
Glycobiology, Apr 1, 2010
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Papers by Piamsook Pongsawasdi