Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 2Citation - Scopus: 2Gas Phase Fragmentation Behavior of Proline in Macrocyclic B7 Ions(American Chemical Society, 2023) Taşoğlu, Çağdaş; Arslanoğlu, Alper; Yalçın, TalatThefragmentation characteristics of b (7) ionsproduced from proline-containing heptapeptides have been studiedin detail. The study has utilized the following C-terminally amidatedmodel peptides: PA(6), APA(5), A(2)PA(4), A(3)PA(3), A(4)PA(2), A(5)PA, A(6)P, PYAGFLV, PAGFLVY, PGFLVYA, PFLVYAG,PLVYAGF, PVYAGFL, YPAGFLV, YAPGFLV, YAGPFLV, YAGFPLV, YAGFLPV, YAGFLVP,PYAFLVG, PVLFYAG, A(2)PXA(3), and A(2)XPA(3) (where X = C, D, F, G, L, V, and Y, respectively). The resultshave shown that b (7) ions undergo head-to-tailcyclization and form a macrocyclic structure. Under the collision-induceddissociation (CID) condition, it generates nondirect sequence ionsregardless of the position of the proline and the neighboring aminoacid residues. This study highlights the unusual and unique fragmentationbehavior of proline-containing heptapeptides. Following the head-to-tailcyclization, the ring opens up and places the proline residue in theN-terminal position while forming a regular oxazolone form of b (2) ions for all peptide series. Then, the fragmentationreaction pathway is followed by the elimination of proline with itsC-terminal neighbor residue as an oxazolone (e.g., PXoxa) for all proline-containing peptide series.Article Citation - WoS: 16Citation - Scopus: 15Gene Cloning, Heterologous Expression, and Partial Characterization of a Novel Cold-Adapted Subfamily I.3 Lipase From Pseudomonas Fluorescence Ke38(Nature Publishing Group, 2020) Karakaş, Fulya; Arslanoğlu, AlperA novel cold-active true lipase from Pseudomonas sp. KE38 was cloned, sequencing and expressed in E. coli by degenerate PCR and genome walking technique. The open reading frame of the cloned gene encoded a polypeptide chain of 617 amino acids with a confirmed molecular weight of 64 kD. Phylogenetic analysis of the deduced amino acid sequence of the lipase indicated that it had high similarity with lipases of subfamily ?.3 of bacterial lipases. Recombinant lipase was purified in denatured form as inclusion bodies, which were then renatured by urea followed by dialysis. Lipase activity was determined titrimetrically using olive oil as substrate. The enzyme showed optimal activity at 25 °C, pH 8.5 and was highly stable in the presence of various metal ions and organic solvents. Low optimal temperature and high activity in the presence of methanol and ethanol make this lipase a potential candidate for transesterification reactions and biodiesel production. © 2020, The Author(s).Article Citation - WoS: 125Citation - Scopus: 156Antimicrobial and Antioxidant Activity of Edible Zein Films Incorporated With Lysozyme, Albumin Proteins and Disodium Edta(Elsevier Ltd., 2007) Mecitoğlu Güçbilmez, Çiğdem; Yemenicioğlu, Ahmet; Arslanoğlu, AlperIn this study, partially purified lysozyme was incorporated into zein films in combination with chickpea albumin extract (CPAE), bovine serum albumin (BSA) and disodium EDTA. The zein films showed an inherent free radical scavenging activity. Incorporation of lysozyme did not contribute to soluble free radical scavenging activity of zein films. However, the incorporation of lysozyme in combination with CPAE increased the soluble and immobilized free radical scavenging activity of zein films 17% to 25% and almost 84%, respectively. The incorporation of CPAE also improved the distribution of partially purified lysozyme preparation in zein films and enabled the controlled release of lysozyme by reducing its release rate from zein films between 1.5- and 3.5-fold, depending on the concentration of incorporated CPAE. In contrast, the BSA incorporation made distribution of lysozyme more heterogeneous and it did not contribute to the free radical scavenging activity of films significantly. The combinational incorporation of partially purified lysozyme with disodium EDTA · 2H2O or CPAE and disodium EDTA · 2H2O gave zein films effective on Escherichia coli and Bacillus subtilis. This study clearly showed the benefits of using functional protein extracts to control lysozyme distribution and release rate and to improve antioxidant activity in zein films.Article Citation - WoS: 125Citation - Scopus: 147Incorporation of Partially Purified Hen Egg White Lysozyme Into Zein Films for Antimicrobial Food Packaging(Elsevier Ltd., 2006) Mecitoğlu, Çiğdem; Yemenicioğlu, Ahmet; Arslanoğlu, Alper; Elmacı, Zehra Seda; Korel, Figen; Çetin, Ali EmrahLysozyme, partially purified from hen egg white by precipitation of non-enzyme protein with ethanol and lyophilized after dialysis, was incorporated into zein films. The recovery and specific activity of the enzyme after partial purification varied between 45% and 72% and 2173 and 3448 U/mg, whereas the activity of the lyophilized enzyme varied between 2900 and 3351 U/mg. The partially purified enzyme was very stable and lost almost no activity in lyophilized form or in zein films stored at -18 and 4°C for up to 8 and 4 months, respectively. During partial purification and in zein film preparation, ethanol treatment caused 123-137% and 132-315% activation of the enzyme, respectively. In zein films incorporated with 187-1318 U/cm2 (63-455 μg/cm2) lysozyme, the release rates at 4°C, changed between 7 and 29 U/cm2/min, increased at high lysozyme concentrations. Zein films incorporated with partially purified lysozyme showed antimicrobial effect on Bacillus subtilis and Lactobacillus plantarum. By the addition of disodium EDTA, the films also became effective on Escherichia coli. The results of this study showed that the partially purified lysozyme may be used in antimicrobial packaging to increase food safety.