Study On Phosphorylation Modification And Bacteriostatic Activity Of Ovotransferrin

Ovotransferrin (OVT) accounted for about12%of the total egg white protein, has abroad spectrum of antibacterial activity, and its bacteriostatic activity was closely relatedwith its structure. In order to improve the bacteriostatic activity of ovotransferrin, sodiumtripolyphosphate was used to modify ovotransferrin. The study further discussed thestructure-activity relationship and the influence of various factors on its antimicrobialactivity. The main research contents and results were as follows:1、 Using sodium tripolyphosphate (STP) phosphorylation modification of eggtransferring, with bacteriostatic activity as the evaluation index, to modify conditions wereoptimized by orthogonal experiments. Test results showed that the optimal modificationprocess conditions were: the pH was9, OVT/STP was1g/10g, reaction time was1h. Afterthe optimized phosphorylation, the phosphorus content of ovotransferrin was4.7%, and theantibacterial activity of ovotransferrin on e.coli was highly significantly improved, theantibacterial activity of ovotransferrin on staphylococcus aureus and bacillus subtilis wassignificantly improved.2、 Zeta potential and isoelectric point determination results showed that afterphosphorylation, the potential of ovotransferrin was obviously decreased, theelectronegativity of ovotransferrin was increased, and the acid isoelectric point ofovotransferrin was drifted: from pH5.39to pH4.79; The results of determination proteinsurface hydrophobicity by ANS fluorescence probe method showed that the hydrophobicgroups of ovotransferrin was exposured after phosphorylation, the surface hydrophobicityof ovotransferrin significantly increased; DSC analysis results showed that afterphosphorylation,the denaturation temperature of ovotransferrin was increased, from59.92℃to66.67℃, and the heat enthalpy change was significantly decreased; Fluorescencespectrum analysis results showed that the fluorescence intensity of ovotransferrin wasdecreased after phosphorylation, it suggested that the tyrosine was involved in the responseand its micro environment was changed; CD spectra analysis results showed that thesecondary and tertiary structure of ovotransferrin was changed, Near-UV CD spectra showedthat tyrosine was involved in the response of phosphorylation, Far-UV CD spectra showed thatthe alpha helix, random coil and the beta angle of ovotransferrin was reduced afterphosphorylation, and the beta–fold was increased; The structure-activity relationship：Raman spectrum analysis results showed ovotransferrin introduced a number of phosphoricacid groups after phosphorylation, and the tyrosine was involved in the response; Theintroduction of the anion on the iron binding sites of ovotransferrin、the development ofmolecular structure and the increase of beta-fold structure of ovotransferrin after phosphorylation made ovotransferrin can more easily combination with the iron, thebacteriostatic activity of ovotransferrin was improved.3、Bacteriostatic test in vitro showed that the MIC and MBC of ovotransferrin onescherichia coli、staphylococcus aureus、bacillus subtilis were decreased; the influence ofthe environment of partial acid and alkaline、high concentrations of salt、high temperatureon bacteriostatic activity of ovotransferrin was big, but after phosphorylation, the influenceof pH、concentration of cationic、temperature on bacteriostatic activity of ovotransferrinwas smaller.