Scopus İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14901/696

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Citation - WoS: 11
Citation - Scopus: 13
Affinity-Based and In a Single Step Purification of Recombinant Horseradish Peroxidase A2a Isoenzyme Produced by Pichia Pastoris
(Springer, 2023) Acar, Melek; Abul, Nurgul; Yildiz, Seyda; Taskesenligil, Ezgi Dag; Gerni, Serpil; Unver, Yagmur; Ozdemir, Hasan
Horseradish peroxidase (HRP) is an oxidoreductase enzyme and oxidizes various inorganic and organic compounds. It has wide application areas such as immunological tests, probe-based test techniques, removal of phenolic pollutants from wastewater and organic synthesis. HRP is found in the root of the horseradish plant as a mixture of different isoenzymes, and it is very difficult to separate these enzymes from each other. In this regard, recombinant production is a very advantageous method in terms of producing the desired isoenzyme. This study was performed to produce HRP A2A isoenzyme extracellularly in Pichia pastoris and to purify this enzyme in a single step using a 3-amino-4-chloro benzohydrazide affinity column. First, codon-optimized HRP A2A gene was amplified and inserted into pPICZ alpha C. So, obtained pPICZ alpha C-HRPA2A was cloned in E. coli cells. Then, P. pastoris X-33 cells were transformed with linearized recombinant DNA and a yeast clone was cultivated for extracellular recombinant HRP A2A (rHRP A2A) enzyme production. Then, the purification of this enzyme was performed in a single step by affinity chromatography. The molecular mass of purified rHRP A2A enzyme was found to be about 40 kDa. According to characterization studies of the purified enzyme, the optimum pH and ionic strength for the rHRP A2A isoenzyme were determined to be 6.0 and 0.04 M, respectively, and o-dianisidine had the highest specificity with the lowest Km and Vmax values. Thus, this is an economical procedure to purify HRP A2A isoenzyme without time-consuming and laborious isolation from an isoenzyme mixture.
Citation - WoS: 8
Citation - Scopus: 7
Combination of Magnetic Hyperthermia and Gene Therapy for Breast Cancer
(Springer, 2025) Solak, Kubra; Arslan, Seyda Yildiz; Acar, Melek; Turhan, Fatma; Unver, Yagmur; Mavi, Ahmet
This study presented a novel breast cancer therapy model that uses magnetic field-controlled heating to trigger gene expression in cancer cells. We created silica- and amine-modified superparamagnetic nanoparticles (MSNP-NH2) to carry genes and release heat under an alternating current (AC) magnetic field. The heat-inducible expression plasmid (pHSP-Azu) was designed to encode anti-cancer azurin and was delivered by magnetofection. MCF-7 cells demonstrated over 93% cell viability and 12% transfection efficiency when exposed to 75 mu g/ml of MSNP-NH2, 3 mu g of DNA, and PEI at a 0.75 PEI/DNA ratio (w: w), unlike non-tumorigenic cells (MCF-10 A). Magnetic hyperthermia (MHT) increased azurin expression by heat induction, leading to cell death in dual ways. The combination of MHT and heat-regulated azurin expression induced cell death, specifically in cancer cells, while having negligible effects on MCF-10 A cells. The proposed strategy clearly shows that simultaneous use of MHT and MHT-induced azurin gene expression may selectively target and kill cancer cells, offering a promising direction for cancer therapy.

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