Amyloidogenic proteins undergo an alternative folding pathway under stressful conditions leading to formation of fibril products, presenting cross β-sheet structure which is the hallmark of many neurodegenerative diseases. The current work demonstrates the effectiveness of phloridzin small molecule on the inhibition of hen egg white LYSOZYME (HEWL) amyloid formation. The inhibitory effects were analyzed by thioflavin T-induced fluorescence, circular dichroism, and atomic force microscopy. This report demonstrated that naturally occurring small molecules may serve a function that is typically done by protein chaperones, and it provides a hint for designing inhibitors against amyloid formation products associated with neurodegenerative diseases. This report showed that phloridzin considerably hindered nucleation, and therefore, fibrillation of LYSOZYME in a dose-dependent manner.

Misfolding and aggregation of various proteins and peptides is associated with a growing list of diseases, including neurodegenerative disorders such as Alzheimer's, Parkinson's, and Huntington's diseases and peripheral disorders such as systemic amyloidosis and type-II diabetes. Consequently, inhibition of protein aggregation and amyloid fibril formation is viewed as one possible method to prevent the progression of these devastating disorders. A promising strategy for preventing of these diseases is to identify compounds that inhibit amyloid fibril formation. Using ThT fluorescence assay, transition electron microscopy and circular dichroism, here we examined the effects of the naturally occurring polyphenol resveratrol on the fibrillogenesis and cytotoxicity of Hen Egg White LYSOZYME (HEWL) fibrils. Our results demonstrate that resveratrol effectively inhibit amyloid fibril formation in a concentration dependent manner. In addition, exciting fibrils of HEWL were disaggregated by resveratrol, as confirmed by ThT fluorescence assay. Furthermore, protective effects of resveratrol against cytotoxicity induced by HEWL fibrils were confirmed using cell viability MTT assay. Although the mechanisms by which resveratrol inhibit fibril formation and destabilize preformed HEWL fibrils are still unclear, we suggest that antioxidative properties as well as anti-amyloidogenic activities of resveratrol underlie its protective effects. It is concluded that naturally occurring polyphenols could serve as scaffold for the design of more efficient inhibitors for amyloid fibril formation in vivo.

Application of LYSOZYME as a natural antimicrobial or preservative agent in food and pharmaceutical industry is well known. The antimicrobial effects of LYSOZYME can be expanded by conjugation with carbohydrates via Maillard reaction, however this natural reaction is a time consuming process. So in this study a new method microwave heating, was applied to Accelerate the Maillard reaction. LYSOZYME was mixed with dextran and heated by microwave irradiation. The glycation extent was determined by SDS-PAGE electrophoresis, cation-exchange chromatography and sugar analysis. SDS-page pattern show that with increasing heating time a high molecular weight conjugates were appeared and maximum glycosylation was occurred after 4 minutes heating. The elution profiles (chromatograms) of the LYSOZYME–dextran conjugates compared the natural LYSOZYME showed that the conjugated peak shifted towards the higher molecular weight fraction and overlapped with the non conjugated proteins, indicated that LYSOZYME was covalently bound to dextran. These results suggest that Maillard reaction rate can be increase using microwave heating.

Effects of b-cyclodextrin, bCD, on refolding of LYSOZYME was investigated at pH 12 employing isothermal titration calorimetry (ITC) at 300K in 30mM Tris buffer solution. bCD was employed as an anti-aggregation agent and the heats obtained for LYSOZYME+bCD interactions are reported and analyzed in terms of the extended solvation model. It was indicated that there are two sets of identical and non-cooperative sites for bCD. Enthalpic force in the first binding sites is more important than entropic one, indicating that electrostatic interaction plays an important role in the interaction of LYSOZYME with bCD. The interaction in the second binding sites is stronger and both enthalpy and entropy driven but hydrophobic interaction has more important than electrostatic force. These results suggest that the effects of bCD on LYSOZYME refolding are attributed to its ability to suppress aggregation of the protein.

Neurodegenerative disease such as Alzheimer, Parkinson and so many related diseases are associated with a form of protein conformational change known as amyloid fibrils product. It was showed that fibrils and protofibrils intermediates are cytotoxic, therefore numerous reports have been attempt to inhibit fibrillation process as a therapeutic methods. Peptides, surfactants and aromatic small molecules have been applied as fibrillation inhibitors. In this report, we examined the interaction of the two natural small molecules (fisetin and diadzin) with hen egg white LYSOZYME (HEWL) for inhibiting the fibril formation products with different kinds of methods such as fluorescence, dynamic light scattering, transmission electron microscopy and circular dichroism. The aim of this study was based on bringing information into possible mechanism of interaction of natural small molecules with amyloied formation products. This report showed that fisetin and diadzinconsiderably hindered nucleation, and therefore, fibrillation of LYSOZYME in a dose-dependent manner.

Aim The aim of the present study was to investigate the biochemical characterizations of the LYSOZYME enzyme for evaluation of its importance in the immune system of the common carp, Cyprinus carpio. Materials & Methods In the present study, LYSOZYME was extracted from the spleen of common carp, Cyprinus carpio. Then, partially purified by ammonium sulfate and some properties such as optimum pH and temperature as well as the effects of different salt concentrations of NaCl, MgCl2, KCl, and urea on enzyme activity were evaluated. The enzyme activity was assayed using a suspension of Micrococcus lysodeikticus as a substrate. Findings The optimum pH and temperature were found 4 and 50° C, respectively. Furthermore, LYSOZYME activity was found to be dependent on salt concentration. Conclusion Based on the results, it’ s been concluded that LYSOZYME extracted from the spleen of the C. carpio has its optimum activity at high temperature and low pH condition and its activity could be continued with the presence of different salt compounds which all these are related to the environmental conditions of natural habitats of the C. carpio and showed that LYSOZYME could be one of the key factors of the immune system in this species.

Protein aggregation is a serious problem for both biotechnology and cell biology. Diseases such as prion misfolding, Alzheimer’s, and other amyloidosis are phenomena for which protein aggregation in our living cells is of considerable relevance. Human LYSOZYME has been shown to form amyloid fibrils in individuals suffering from nonneuropathic systemic amyloidosis, all of which have point mutations in the LYSOZYME gene. In this study, we investigated effect of small additives on the thermal aggregation of LYSOZYME. The main finding of this work is that multiple amine groups, spermine and spermidine, play pivotal roles in preventing the thermal aggregation of LYSOZYME. Our results showed that effect of spermine is more than spermidine.

Gold nanoparticles are promising materials for biomedical applications because of the attractive optical properties such as the absorption and scattering of light at resonant wavelength. Due to the fruitful applications of gold nanoparticles (GNPs), they are appropriate for a variety of biological studies. One of the most important applications of nanoparticles is protein carriers, in which transport of therapeutically relevant protein is done to in vivo or in vitro targets. Protein folding and properties of probable intermediates during the folding of proteins had been investigated in several studies. The molten globule state, a main intermediate of protein folding, has native-like secondary but perturbation of tertiary structure. Consequently, the influence of gold nanoparticles concentration on a model protein was studied by far-and near-UV circular dichroism (CD), Fourier transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), intrinsic fluorescence emission spectroscopy and 8-Anilino-1naphthalenesulfonic acid binding. The results indicated that the interactions between gold nanoparticles and LYSOZYME lead to the formation of molten globule-like state.

Adsorption of proteins on inorganic surfaces may lead to structural and functional changes that are dependent on both the nature of the adsorbed proteins and the physicochemical properties of the inorganic surfaces. Chicken egg white LYSOZYME (E.C 3.2.1.17, MW=14.6 kDa) is a small globular protein, that consists of 129 amino acid residues with four disulfide bonds. The aim of this study was the survey of the stability and structure of Chicken egg white LYSOZYME against ZnO nano through thermal stability, fluorescence and spectroscopy and enzyme activity assay in the absence or presence of ZnO nano particle at pH 7.0. The obtained results indicated that thermal stability and activity of LYSOZYME decreased with increase in ZnO nanoparticles concentration. Moreover, it was observed that ZnO Nano particle quenched the intrinsic fluorescence of LYSOZYME. The interaction studies of ZnO nanoparticles and LYSOZYME show that not only water and solvent molecules can effect on 3D structure of LYSOZYME and protein but also play an important role in adsorption nanoparticles.

Recent investigations show that fibrillation products and intermediates bring neurotoxicity. Inhibition of protein aggregation and amyloid fibril formation are viewed as one possible method to prevent the progression of these devastating disorders. This toxicity is predominantly associated to their intermediate oligomeric state. This has been demonstrated to be induced by enhancing membrane permeability and perturbation, eventually leading to cell death. In the present report, we study interaction of the two small molecules (safranal and crocin) with hen egg white LYSOZYME (HEWL) for inhibiting the fibril formation with different kind of methods such as fluorescence, dynamic light scattering, transmission electron microscopy and circular dichroism. The aim of this report was based on gaining insight into possible mechanism of interaction of small molecules with amyloied formation products. These studies demonstrated that safranal and crocin considerably hindered nucleation, and therefore, fibrillation of LYSOZYME in a dose-dependent manner.