muramidase and hydroquinone

Topics: Aptamers, Nucleotide; Armoracia; Base Sequence; Biosensing Techniques; Electrochemical Techniques; Gold; Horseradish Peroxidase; Humans; Hydrogen Peroxide; Hydroquinones; Limit of Detection; Metal Nanoparticles; Muramidase; Reproducibility of Results

Numerous phenolic compounds have been reported to have an inhibitory role on amyloid formation of proteins. The present study, utilizing lysozyme as a model system, examined the anti-amyloidogenic effects of phenol and three diphenol epimers. The results indicated that catechol and hydroquinone dose-dependently inhibited lysozyme fibrillation and covalently bound to the peptide chains to form quinoproteins, showing a similar effect to benzoquinone. In contrast, phenol and resorcinol did not modify the peptide with a quinone moiety, showing no effect on lysozyme fibrillation. We suggest that quinone intermediates are the active form for a phenolic compound to inhibit lysozyme fibrillation. The modification of lysozyme with quinone moieties alters the interacting forces between peptide chains and consequently interrupts the process of lysozyme fibrillation.

Topics: Amyloid; Benzoquinones; Catechols; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Hydroquinones; Kinetics; Microscopy, Electron, Transmission; Molecular Structure; Muramidase; Phenols; Protein Binding; Resorcinols

In septic shock, systemic vasodilation and myocardial depression contribute to the systemic hypotension observed. Both components can be attributed to the effects of mediators that are released as part of the inflammatory response. We previously found that lysozyme (Lzm-S), released from leukocytes, contributed to the myocardial depression that develops in a canine model of septic shock. Lzm-S binds to the endocardial endothelium, resulting in the production of nitric oxide (NO), which, in turn, activates the myocardial soluble guanylate cyclase (sGC) pathway. In the present study, we determined whether Lzm-S might also play a role in the systemic vasodilation that occurs in septic shock. In a phenylephrine-contracted canine carotid artery ring preparation, we found that both canine and human Lzm-S, at concentrations similar to those found in sepsis, produced vasorelaxation. This decrease in force could not be prevented by inhibitors of NO synthase, prostaglandin synthesis, or potassium channel inhibitors and was not dependent on the presence of the vascular endothelium. However, inhibitors of the sGC pathway prevented the vasodilatory activity of Lzm-S. In addition, Aspergillus niger catalase, which breaks down H(2)O(2), as well as hydroxyl radical scavengers, which included hydroquinone and mannitol, prevented the effect of Lzm-S. Electrochemical sensors corroborated that Lzm-S caused H(2)O(2) release from the carotid artery preparation. In conclusion, these results support the notion that when Lzm-S interacts with the arterial vasculature, this interaction results in the formation of H(2)O(2), which, in turn, activates the sGC pathway to cause relaxation. Lzm-S may contribute to the vasodilation that occurs in septic shock.

Topics: Aminoquinolines; Animals; Carotid Artery, Internal; Catalase; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Cyclooxygenase Inhibitors; Dogs; Dose-Response Relationship, Drug; Enzyme Inhibitors; Ethanol; Free Radical Scavengers; Guanylate Cyclase; Humans; Hydrogen Peroxide; Hydroquinones; In Vitro Techniques; Indomethacin; Mannitol; Mesenteric Artery, Superior; Methylene Blue; Muramidase; Nitric Oxide; Nitric Oxide Synthase; omega-N-Methylarginine; Oxadiazoles; Phenylephrine; Prostaglandins; Protein Kinase Inhibitors; Quinoxalines; Receptors, Cytoplasmic and Nuclear; Sepsis; Signal Transduction; Soluble Guanylyl Cyclase; Thionucleotides; Time Factors; Vasoconstrictor Agents; Vasodilation