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    Improved chromatographic method for purification of lactoperoxidase from different milk sources
    (Taylor & Francis Inc, 2017) Koksal, Zeynep; Usanmaz, Hande; Bayrak, Songul; Ozdemir, Hasan
    Our previous studies showed that sulfanilamide is a new competitive inhibitor of and can be used in the purification of lactoperoxidase (LPO, EC1.11.1.7) from milk. However, this method has some disadvantages like a lower purification factor. The aim of the present study is to improve the purification process of milk LPO from different sources. For this purpose, 16 commercial sulfanilamide derivatives were selected for inhibition studies to determine the best inhibitor of bovine LPO by calculating kinetic parameters. A cyanogen bromide-activated Sepharose 4B affinity matrix was synthesized by coupling with each competitive inhibitor. Among the inhibitors, 5-amino-2-methylbenzenesulfonamide and 2-chloro-4-sulfamoylaniline were used as ligands for the purification of LPO from bovine, buffalo, cow, and goat milks with 1059.37, 509.09, 232.55, and 161.90, and 453.12-, 151.86-, 869.00-, and 447.57-fold, respectively. Our results show that 5-amino-2-methylbenzenesulfonamide, 2-chloro-4sulfamoylaniline, and 5-amino-1-naphthalenesulfonamide are the best inhibitors for one-step purification of the enzyme.
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    Öğe
    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; Karaman, Muhammet
    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
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    Öğe
    Secondary Sulfonamides as Effective Lactoperoxidase Inhibitors
    (Mdpi, 2017) Koksal, Zeynep; Kalin, Ramazan; Camadan, Yasemin; Usanmaz, Hande; Almaz, Zuleyha; Gulcin, Ilhami; Gokcen, Taner
    Secondary sulfonamides (4a-8h) incorporating acetoxybenzamide, triacetoxybenzamide, hydroxybenzamide, and trihydroxybenzamide and possessing thiazole, pyrimidine, pyridine, isoxazole and thiadiazole groups were synthesized. Lactoperoxidase (LPO, E.C.1.11.1.7), as a natural antibacterial agent, is a peroxidase enzyme secreted from salivary, mammary, and other mucosal glands. In the present study, the in vitro inhibitory effects of some secondary sulfonamide derivatives (4a-8h) were examined against LPO. The obtained results reveal that secondary sulfonamide derivatives (4a-8h) are effective LPO inhibitors. The K-i values of secondary sulfonamide derivatives (4a-8h) were found in the range of 1.096 x 10(-3) to 1203.83 mu M against LPO. However, the most effective inhibition was found for N-(sulfathiazole)-3,4,5-triacetoxybenzamide (6a), with K-i values of 1.096 x 10(-3) +/- 0.471 x 10(-3) mu M as non-competitive inhibition.