Colorimetric Determination of the Activity of Starch-Debranching Enzyme via Modified Tollens’ Reaction

Luo, Ke; Kim, Nack-geun; You, Sang-Mook; Kim, Young-Rok

doi:10.3390/nano9091291

Cited by 15 publications

(6 citation statements)

References 26 publications

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“…16,17 Therefore, eliminating α-1,6 branches by debranching enzymes (DBEs) during starch degradation is a critical and well-established approach to facilitate starch hydrolysis and improve production efficiency. 18 DBEs are a type of starch-degrading enzyme that can specifically act on α-1,6-linkages in glycogen, amylopectin, and related polysaccharides. They can be classified into different groups according to the differences in substrate specificity and catalytic mode.…”

Section: Introductionmentioning

confidence: 99%

“…Besides, starch can be also applied to produce cyclodextrin and oligosaccharides through the action of cyclodextrin glycosyltransferase (EC 2.4.1.19) and maltooligosaccharide-forming amylases (EC 3.2.1.-), respectively. − Although various amylolytic enzymes have been used in starch processing, most of them are very expensive or inefficient in starch conversion . The majority of α-amylase, β-amylase, and α-glucosidase enzymes can hydrolyze α-1,4-glucosidic linkages in starch but have low activities for α-1,6-linkages, , resulting in a low overall conversion rate of starch material and large amounts of byproducts. , Therefore, eliminating α-1,6 branches by debranching enzymes (DBEs) during starch degradation is a critical and well-established approach to facilitate starch hydrolysis and improve production efficiency …”

Section: Introductionmentioning

confidence: 99%

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Distribution of Aromatic Amino Acid Residues in Substrate-Binding Regions Modulates Substrate Specificity of Microbial Debranching Enzymes

Tian

Kong

Ban

et al. 2023

J. Agric. Food Chem.

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Debranching enzymes (DBEs) directly hydrolyze α-1,6-glucosidic linkages in glycogen, starch, and related polysaccharides, making them important in the starch processing industry. However, the ambiguous substrate specificity usually restricts synergistic catalysis with other amylases for improving starch utilization. Herein, a glycogen-debranching enzyme from Saccharolobus solfataricus (SsGDE) and two isoamylases from Pseudomonas amyloderamosa (PaISO) and Chlamydomonas reinhardtii (CrISO) were used to investigate the molecular mechanism of substrate specificity. Along with the structure-based computational analysis, the aromatic residues in the substrate-binding region of DBEs played an important role in binding substrates. The aromatic residues in SsGDE appeared clustered, contributing to a small substrate-binding region. In contrast, the aromatic residues in isoamylase were distributed dispersedly, forming a large active site. The distinct characteristics of substrate-binding regions in SsGDE and isoamylase might explain their substrate preferences for maltodextrin and amylopectin, respectively. By modulating the substrate-binding region of SsGDE, variants Y323F and V375F were obtained with significantly enhanced activities, and the activities of Y323F and V375F increased by 30 and 60% for amylopectin, and 20 and 23% for DE4 maltodextrin, respectively. This study revealed the molecular mechanisms underlying the substrate specificity for SsGDE and isoamylases, providing a route for engineering enzymes to achieve higher catalytic performance.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Distribution of Aromatic Amino Acid Residues in Substrate-Binding Regions Modulates Substrate Specificity of Microbial Debranching Enzymes

Tian

Kong

Ban

et al. 2023

J. Agric. Food Chem.

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“…The time was 10.80 min. The total protein content was determined by the Kjeldahl nitrogen determination method, 11 and starch and reductive sugar contents were determined using 3,5‐dinitrosalicylic acid (DNS) 12 …”

Section: Methodsmentioning

confidence: 99%

“…The total protein content was determined by the Kjeldahl nitrogen determination method, 11 and starch and reductive sugar contents were determined using 3,5-dinitrosalicylic acid (DNS). 12 Determination of enzyme activity All samples were freeze-dried completely. Their liquefaction and saccharification capacity was analyzed and optimized following methods reported previously.…”

Section: Analysis Of Basic Indicatorsmentioning

confidence: 99%

The differences in main components, enzyme activity, and microbial composition between substandard and normal jiuyao

Zhao

Zhou

et al. 2023

J Sci Food Agric

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BACKGROUND Jiuyao is a critical fermenting agent in traditional huangjiu brewing and it affects the quality of huangjiu. To assess and monitor the quality of jiuyao effectively we determined the differences between two common types of substandard jiuyao and normal jiuyao, with emphasis on the comparison of the main components, enzymatic activity, volatile substances, and microbial community structure. RESULTS The water and starch content, acid protease activity, and esterification capability of type I substandard jiuyao were significantly lower than those of the normal jiuyao, and the protein contents, liquefaction capability, glycation capability, and neutral protease activity were substantially higher than those of the normal jiuyao. Type II substandard jiuyao had significantly lower indices than the normal group except for the starch and free amino acid content, which were significantly higher than those of the normal jiuyao. Significant differences were observed between substandard and normal jiuyao in the content of 21 volatile compounds. 2‐Pentylfuran could be used as a marker of substandard jiuyao. Type I substandard jiuyao contained a higher abundance of aerobic Pediococcus and Marivita in comparison with the normal jiuyao. Type II substandard jiuyao consisted of a greater abundance of anaerobic Mucor and Staphylococcus. CONCLUSION The quality of jiuyao was significantly affected by the water content. Due to the different abundances of aerobic and anaerobic bacteria in jiuyao, oxygen may also be an important parameter affecting the quality of jiuyao. We believe that the present study offers a theoretical basis for the evaluation and control of the quality of jiuyao. © 2023 Society of Chemical Industry.

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“…SMBs were prepared by the self-assembly of short-chain glucans (SCGs) together with iron oxide nanoparticles (IONPs) into a spherical form, as reported by Luo et al − Briefly, iron oxide nanoparticles (IONPs) were prepared by coprecipitation of ferrous and ferric salts in a 2:1 molar ratio (80 and 40 mM, respectively) in 20 mL of deionized water (DW) containing 150 mg of dextran. The mixture was sonicated by a Q500 Sonicator (VC 750, Sonics & Materials Inc., Newtown, CT) in an ice bath for 3 min with an on/off cycle of 3/3 s at 30% amplitude through a 6 mm probe.…”

Section: Experimental Sectionmentioning

confidence: 99%

Gold Nanoparticle-Coated Starch Magnetic Beads for the Separation, Concentration, and SERS-Based Detection of E. coli O157:H7

You

Luo

Jung

et al. 2020

ACS Appl. Mater. Interfaces

Self Cite

102

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Here, we report gold nanoparticle-coated starch magnetic beads (AuNP@SMBs) that were prepared by in situ synthesis of AuNPs on the surface of SMBs. Upon functionalization of the surface with a specific antibody, the immuno-AuNP@SMBs were found to be effective in separating and concentrating the target pathogenic bacteria, Escherichia coli O157:H7, from an aqueous sample as well as providing a hotspot for surface-enhanced Raman scattering (SERS)-based detection. We employed a bifunctional linker protein, 4× gold-binding peptide-tagged Streptococcal protein G (4GS), to immobilize antibodies on AuNP@SMBs and AuNPs in an oriented form. The linker protein also served as a Raman reporter, exhibiting a strong and unique fingerprint signal during the SERS measurement. The amplitude of the SERS signal was shown to have a good correlation with the concentration of target bacteria ranging from 100 to 105 CFU/mL. The detection limit was determined to be as low as a single cell, and the background signals derived from nontarget bacteria were negligible due to the excellent specificity and colloidal stability of the immuno-AuNP@SMBs and SERS tags. The highly sensitive nature of the SERS-based detection system will provide a promising means to detect the pathogenic microorganisms in food or clinical specimen.

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Colorimetric Determination of the Activity of Starch-Debranching Enzyme via Modified Tollens’ Reaction

Cited by 15 publications

References 26 publications

Distribution of Aromatic Amino Acid Residues in Substrate-Binding Regions Modulates Substrate Specificity of Microbial Debranching Enzymes

Distribution of Aromatic Amino Acid Residues in Substrate-Binding Regions Modulates Substrate Specificity of Microbial Debranching Enzymes

The differences in main components, enzyme activity, and microbial composition between substandard and normal jiuyao

Gold Nanoparticle-Coated Starch Magnetic Beads for the Separation, Concentration, and SERS-Based Detection of E. coli O157:H7

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