Browsing by Author "Gerni, Serpil"

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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.
The Inhibition Effects of Some Natural Products on Lactoperoxidase Purified from Bovine Milk
(Wiley, 2017) Koksal, Zeynep; Kalin, Ramazan; Gerni, Serpil; Gulcin, Ilhami; Ozdemir, Hasan
In this study, inhibition profiles of some natural products, which are digoxin, L-Dopa, dopamine, isoliquiritigenin, and 1,1,2,2-tetrakis(p-hydroxyphenyl)ethane (Tetrakis), were investigated against bovine lactoperoxidase (LPO) enzyme. Digoxin, L-Dopa, and dopamine are active ingredients of some drugs, which have important functions in our body, especially in cases of heart failure. Isoliquiritigenin and tetrakis are types of natural phenolic compounds, which play an important role in cancer prevention and treatment. LPO enzyme was purified from bovine milk using sepharose-4B-l-tyrosine sulfonamide affinity column chromatography. LPO is responsible for the nonimmune biological defense system and has antibacterial activity so selection of these active substances is important. The inhibition studies are performed with the ABTS substrate. Bovine LPO enzyme was effectively inhibited by phenolic molecules. K-i values of these natural products were found as 0.20 +/- 0.09, 0.22 +/- 0.17, 0.49 +/- 0.11, 0.49 +/- 0.27, and 1.20 +/- 0.25 M, respectively. Tetrakis and digoxin exhibited noncompetitive inhibition, and other molecules showed competitive inhibition.
Molecular Docking and Inhibition Profiles of Some Antibiotics on Lactoperoxidase Enzyme Purified from Bovine Milk
(Taylor & Francis Inc, 2022) Kalin, Ramazan; Koksal, Zeynep; Bayrak, Songul; Gerni, Serpil; Ozyurek, Isil Nihan; Usanmaz, Hande; Gulcin, Ilhami
Antibiotics are generally used for human and veterinary applications to preserve and to control microbial diseases. Milk has a biologically significant enzyme known as lactoperoxidase (LPO) that is a member of peroxidase family. In metabolism, LPO has ability to catalyze the transformation of thiocyanate (SCN-) to hypothiocyanite (OSCN-) that is an antibacterial agent and the reaction occurs with hydrogen peroxide. In this work, LPO inhibition effects of some antibiotics including cefazolin, oxytetracycline, flunixin meglumine, cefuroxime, tylosin, vancomycin, chloramphenicol and lincomycin were tested. Among the antibiotics cefazolin was indicated the strongest inhibitory efficacy. The half maximal inhibitory concentration (IC50) and the inhibition constant (K-i) values of cefazolin were found as 8.19 and 34.66 mu M, respectively. It was shown competitive inhibition. 5-Methyl-1,3,4-thiadiazol-2-yl moiety activity plays a key role in the inhibition mechanism of cefazolin. Communicated by Ramaswamy H. Sarma
A New Affinity Matrix Synthesized from Aminobenzohydrazide Derivatives for Purification of Lactoperoxidase Enzyme
(Wiley-V C H Verlag GmbH, 2022) Kavaz, Neslihan Macit; Erel, Deniz; Korkmaz, Isil Nihan; Gerni, Serpil; Abul, Nurgul; Bayrak, Songul; Ozdemir, Hasan
In this study, a new affinity process was developed for the purification of Lactoperoxidase with synthesized sixteen aminobenzohydrazide derivatives. For this purpose, ligands were covalently bound to CNBr-activated Sepharose-4B-L-tyrosine matrix and affinity columns were prepared, and LPO was purified in one step with high yield and purity. Among all synthesized molecules, the 4-amino-3-bromo-2-methylbenzohydrazide molecule had a high usable potential in the purification of Lactoperoxidase from mammalian milk. Lactoperoxidase was purified 411.8 times with a yield of 17.38 % from goat milk, 187.25 times with a yield of 9.72 % buffalo milk, 2772.4 times with a yield of 18.98 % from bovine milk, and 1246.65 times with a yield of 4.43 % from sheep milk. It was demonstrated for the first time that aminobenzohydrazide molecules could be used as ligands in the purification of Lactoperoxidase enzyme.