Immobilization of α-Amylase onto Quantum Dots Prepared from Hypericum perforatum L. Flowers and Hypericum capitatum Seeds: Its Physicochemical and Biochemical Characterization

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dc.contributor.authorAcari, Idil Karaca
dc.contributor.authorDik, Gamze
dc.contributor.authorBakar, Busra
dc.contributor.authorUlu, Ahmet
dc.contributor.authorOnal, Yunus
dc.contributor.authorAtes, Burhan
dc.date.accessioned2026-06-19T06:41:05Z
dc.date.available2026-06-19T06:41:05Z
dc.date.issued2023
dc.departmentMalatya Turgut Özal Üniversitesi
dc.description.abstractEnzyme immobilization is an effective way to increase the catalytic activity and stability of the alpha-amylase (Amy) enzyme for industrial uses. For this purpose, carbon and graphene quantum dot (QDs) structures were prepared from Hypericum perforatum L. flowers (QD-1), and Hypericum capitatum seeds (QD-2) obtained from an herbalist in Hatay province of Turkey. Structural and morphological characterization of the prepared QDs and QDs/Amy were carried out by Fourier transform infrared spectrophotometer (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray (EDX). Meanwhile, biochemical characterizations such as optimum pH and temperature, kinetic parameters, effects of metal ions, organic solvents, and trypsin digestion on enzyme activity were performed and compared with free Amy. The Amy enzyme was immobilized with an activity efficiency of 71.15% for QD-1/Amy, and 81.51% for QD-2/Amy under optimal conditions. The difference in activity efficiency between QD-1/Amy and QD-2/Amy was likely due to a change in the surface porosity of QDs structures. While the optimal pH value of all three forms of Amy was recorded as 6.0, their optimal temperature was found to be 40 degrees C. The activation energy (E-a) of the free Amy was found to be 4.81 kJ/mol, while it was 9.61 kJ/mol, and 3.20 kJ/mol for QD-1/Amy, and QD-2/Amy, respectively. K-m values were calculated as 1.18, 1.57, and 1.35 mg/mL for free Amy, QD-1/Amy, and QD-2/Amy, respectively, and V-max values were calculated as 37.52, 37.60, and 39.93 mu mol/min, respectively. Kinetic data revealed that the immobilized enzymes had lower substrate affinity compared to the free Amy. Besides, the QD-1/Amy and QD-2/Amy exhibited more stability than free Amy against metal ions, organic solvents as well as trypsin digestion due to the increment in conformational rigidity caused by changes in the secondary structures of the immobilized enzyme. For instance, after incubation with trypsin for 120 min, free Amy, QD-1/Amy, and QD-2/Amy retained approximately 20%, 35%, and 26% of initial activities, respectively. Finally, it can be proposed that the prepared carriers in this work may a useful to produce stable and active immobilized Amy to be used in industrial applications.
dc.description.sponsorshipScientific Research Projects Unit of Inonu University
dc.description.sponsorshipThe authors thank the Scientific Research Projects Unit of Inonu University.
dc.identifier.doi10.1007/s11244-022-01699-y
dc.identifier.endpage576
dc.identifier.issn1022-5528
dc.identifier.issn1572-9028
dc.identifier.issue9-12
dc.identifier.orcid0000-0003-4798-8127
dc.identifier.orcid0000-0001-6080-229X
dc.identifier.orcid0000-0001-6342-6816
dc.identifier.orcid0000-0001-6783-7030
dc.identifier.scopus2-s2.0-85137449607
dc.identifier.scopusqualityQ2
dc.identifier.startpage563
dc.identifier.urihttps://doi.org/10.1007/s11244-022-01699-y
dc.identifier.urihttps://hdl.handle.net/20.500.12899/6058
dc.identifier.volume66
dc.identifier.wosWOS:000849488400001
dc.identifier.wosqualityQ2
dc.indekslendigikaynakWeb of Science
dc.indekslendigikaynakScopus
dc.language.isoen
dc.publisherSpringer/Plenum Publishers
dc.relation.ispartofTopics in Catalysis
dc.relation.publicationcategoryMakale - Uluslararası Hakemli Dergi - Kurum Öğretim Elemanı
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.snmzKA_WOS_20260612
dc.subjectEnzyme Immobilization
dc.subjectAlpha-Amylase
dc.subjectHypericum Perforatum L.
dc.subjectHypericum Capitatum
dc.subjectQuantum Dots
dc.subjectImproved Stability
dc.titleImmobilization of α-Amylase onto Quantum Dots Prepared from Hypericum perforatum L. Flowers and Hypericum capitatum Seeds: Its Physicochemical and Biochemical Characterization
dc.typeArticle

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