muramidase and ferulic-acid

In this study, ferulic acid-modified water soluble chitosan and poly (γ-glutamic acid) polyelectrolyte multilayers films were constructed through the layer-by-layer (LBL) self-assembly technique. Chitosan (CS) or ferulic acid modified chitosan (MCS) and Poly (γ-glutamic acid) (PGA) was alternately deposited on the surface of glass substrate for the enhancement of surface modification. The obtained films were characterized by Fourier transform spectroscopy (FTIR), X-ray diffractometry (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and water contact angle to study its physico-chemical properties including protein absorption. The (PGA/MCS) films showed intense deposition of multilayers built upon the surface roughness and an increase in the exponential growth of multilayer films by UV-vis spectroscopy. Water contact angle indicated that the (PGA/MCS) films performed well with good wettability due to the increase in the number of layers. The LBL multilayer coatings of (PGA/MCS) films surface possessed a reduced amount of protein adsorption. These results indicated that it can resist the protein adsorption and can enhance the biocompatibility towards the biomedical application through the protein interaction. The (PGA/MCS) films has the potential to utilization as a good biomaterial for biomedical purposes to intensify the bio-active surface.

Topics: Adsorption; Chemistry Techniques, Analytical; Chitosan; Coated Materials, Biocompatible; Coumaric Acids; Hydrophobic and Hydrophilic Interactions; Materials Testing; Microscopy, Electron, Scanning; Muramidase; Polyelectrolytes; Polyglutamic Acid; Serum Albumin, Bovine; Solubility; Surface Properties; Water

The efficiency of laccase-catalyzed protein cross-linking can be impacted by substrate protein structure and competing reactions. In this study, chemical grafting of ferulic acid (FA) on protein surface was applied to modulate the cross-linking of two inflexible globular proteins, lysozyme (LZM) and ovalbumin (OVA). The extent of FA-grafting was positively correlated with protein cross-linking extent, and determined the molecular weight profile and structures of the cross-linked product. While laccase-catalyzed reactions (with or without free FA mediator) did not lead to evident cross-linking of the native proteins, oligomeric (up to 16.4%), polymeric (up to 30.6%) FA-LZMs and oligomeric FA-OVA (5.1-31.1%) were obtained upon the enzymatic treatments. The cross-linking on the grafted FA sites occurred mainly through the formation of 8-5'-noncyclic-dehydro-diferulic linkages. The effects of investigated cross-linking approach on the emulsifying, foaming properties and the immunoglobulin E (IgE) binding capacity of LZM and OVA were also evaluated in relation to the structural properties of cross-linked proteins.

Topics: Antigen-Antibody Reactions; Biocatalysis; Coumaric Acids; Cross-Linking Reagents; Humans; Immunoglobulin E; Laccase; Molecular Weight; Muramidase; Ovalbumin; Oxidation-Reduction; Phenols

The noncovalent binding of selected phenolic compounds (chlorogenic-, ferulic-, gallic acid, quercetin, rutin, and isoquercetin) to proteins (HSA, BSA, soy glycinin, and lysozyme) was studied by an indirect method applying the quenching of intrinsic tryptophan fluorescence. From the data obtained, the binding constants were calculated by nonlinear regression (one site binding; y = Bx/k + x). It has been reported that tannins inhibit human salivary amylase and that these complexes may reduce the development of cariogenic plaques. Further, amylase contains two tryptophan residues in its active site. Therefore, in a second part of the study involving 31 human subjects, evidence was sought for noncovalent interactions between the phenols of green tea and saliva proteins as measured by the fluorescence intensity. Amylase activity was determined before and after the addition of green tea to saliva of 31 subjects. Forty percent of the subjects showed an increase in amylase activity contrary to studies reporting only a decrease in activity. The interactions of tannin with amylase result in a decrease of its activity. It still remains to be elucidated why amylase does not react uniformly under conditions of applying green tea to saliva. Further, in terms of using phenols as caries inhibitors this finding should be of importance.

Topics: Amylases; Binding Sites; Chlorogenic Acid; Coumaric Acids; Fluorescence; Gallic Acid; Globulins; Humans; Muramidase; Phenols; Proteins; Quercetin; Regression Analysis; Rutin; Saliva; Serum Albumin; Serum Albumin, Bovine; Soybean Proteins; Tannins; Tea; Thermodynamics; Tryptophan

In the context of this study, the noncovalent binding of selected phenolic compounds (chlorogenic, ferulic, and gallic acids, quercetin, rutin, and isoquercetin) to different proteins (human serum albumin, bovine serum albumin, soy glycinin, and lysozyme) was studied with direct (Hummel-Dreyer/size exclusion chromatography) and/or indirect methods (fluorescence absorbance properties of the binding components). In the latter case, the measurement of the phenol binding was achieved by exploiting the intrinsic fluorescence emission properties of quercetin as a probe. From the data obtained, the binding constants and the number of binding sites were calculated. The binding parameters were influenced by different factors, where, e.g., increasing temperature and ionic strength as well as decreasing pH cause a diminished binding. The structures of the proteins as determined by circular dichroism indicate changes in the tertiary structure with the secondary structure remaining intact.

Topics: Animals; Binding Sites; Cattle; Chromatography, Gel; Coumaric Acids; Globulins; Hot Temperature; Humans; Hydrogen-Ion Concentration; Mathematics; Muramidase; Osmolar Concentration; Phenols; Protein Binding; Proteins; Quercetin; Serum Albumin; Soybean Proteins

Selected enzymes (alpha-amylase, trypsin, and lysozyme) were allowed to react with some simple phenolic and related compounds (caffeic acid, chlorogenic acid, ferulic acid, gallic acid, m-, o-, and p-dihydroxybenzenes, quinic acid, and p-benzoquinone). The derivatized enzymes obtained were characterized in terms of their activity. In vitro experiments showed that the enzymatic activity of the derivatives was adversely affected. This enzyme inhibition depended on the reactivity of the phenolic and related substances tested as well as on the kind of substrate applied. The decrease in the activity was accompanied by a reduction in the amount of free amino and thiol groups, as well as tryptophan residues, which resulted from the covalent attachment of the phenolic and related compounds to these reactive nucleophilic sites in the enzymes. The enzyme inhibition correlates well with the blocking of the mentioned amino acid side chains.

Topics: alpha-Amylases; Benzoquinones; Caffeic Acids; Chlorogenic Acid; Coumaric Acids; Enzyme Inhibitors; Gallic Acid; Hydroquinones; Muramidase; Phenols; Plants; Quinic Acid; Trypsin; Trypsin Inhibitors