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Matrix-assisted pulsed laser evaporation of β-glucosidase from a dopa/quinone target
摘要： β-glucosidase (BG) plays a key role in determining the efficiency of the enzymatic complex cellulase for the degradation of cellulose into sugars. It hydrolyses the cellobiose, an inhibitor of the enzymatic complex. Therefore, the immobilization of BG is a great challenge for the industrial application of cellulases. Cellulases usually contains a BG amount insufficient to avoid inhibition by cellobiose. Here the BG was immobilized by matrix assisted pulsed laser evaporation (MAPLE) technique. The frozen matrix was composed of water, water/m-DOPA and water/m-DOPA/quinone. The effect of the excipients on the final conformation of the enzyme after the MAPLE processing was determined. The enzyme secondary structure was studied by FTIR analysis. The catalytic performances of the deposited films were tested in the cellobiose hydrolysis reaction. The results demonstrate that the presence of the oxidized form of m-DOPA, the O-quinone form, can protect the protein native structure, with the laser inducing little or no damage. In fact, only the samples deposited from this target preserved the secondary structure of the polypeptide chain and allowed a complete hydrolysis of cellobiose for four consecutive runs, showing a high operational stability of the biocatalyst.
关键词： MAPLE,β-glucosidase,Thin films,Protein conformation,m-DOPA,O-quinone
更新于2025-09-12 10:27:22
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A label-free fluorescent sensor based on silicon quantum dots–MnO <sub/>2</sub> nanosheets for the detection of α-glucosidase and its inhibitor
摘要： A label-free fluorescent sensor based on silicon quantum dots–MnO2 nanosheets for the detection of α-glucosidase and its inhibitor?. α-Glucosidase and its inhibitors play a key role in diagnosis and treatment of diabetes. In the present work, we established a facile, sensitive and selective fluorescence method based on silicon quantum dots (SiQDs) and MnO2 nanosheets for the determination of α-glucosidase and one of its inhibitors acarbose. The fluorescence of SiQDs was greatly quenched by MnO2 nanosheets due to the inner filter effect. α-Glucosidase could easily catalyze the hydrolysis of L-ascorbic acid-2-O-α-D-glucopyranosyl (AAG) to produce ascorbic acid (AA), which could reduce MnO2 nanosheets to Mn2+, resulting in dramatic recovery of the fluorescence of SiQDs. The proposed sensing platform could provide a good linear relationship between the fluorescence intensity of SiQDs and the concentration of α-glucosidase in the range of 0.02–2.5 U mL?1 with a detection limit of 0.007 U mL?1. In addition, the sensing platform could be used for α-glucosidase inhibition. Acarbose was one of the most common and typical inhibitors, and this sensing platform can be utilized to detect acarbose in the range of 1–1000 μM. The developed fluorescence method was successfully validated for the determination of α-glucosidase in human serum samples.
关键词： silicon quantum dots,acarbose,label-free fluorescent sensor,MnO2 nanosheets,α-glucosidase
更新于2025-09-12 10:27:22