Detection of the PRAME Protein on the Surface of Melanoma Cells Using a Fluorescently Labeled Monoclonal Antibody

Abstract: Determination of the expression level of tumor marker PRAME protein is important both for predicting the course of the disease and for monitoring the effectiveness of anticancer therapy. A fluorescently labeled monoclonal antibody to the PRAME protein was obtained by periodate oxidation of glycans followed by modification with a bifunctional azido-oxyamine reagent and a “click” reaction with alkyne-modified sulfonated cyanine dye Cy3. A new approach to the synthesis of a bifunctional azido-oxyamine reagent using the ethoxyethylidene protecting group for oxyamine is proposed. The labeled antibodies were characterized with UV/Vis absorption spectra and the stoichiometry of the modification was determined. It has been demonstrated that the fluorescent antibodies retain affinity and can be used as a diagnostic tool for detecting the residual marker (the PRAME protein) after anticancer therapy. © 2021, Pleiades Publishing, Ltd

Investigation of the complex antibiotic INA-5812

A concentrate with the antimicrobial activity has been isolated from the culture broth of Streptomyces roseoflavus INA-Ac-5812. Its further fractionation by reversed-phase HPLC has resulted in six fractions. It has been established by MALDI-TOF and ESI-MSn precision mass-spectrometry methods that the main components of the complex antibiotic are several closely related compounds, presumably of a glycopeptide nature. The fraction containing an individual component with a mass of 1845.788 Da has been characterized by UV/Vis absorbance and fluorescence spectra, amino acid analysis, and derivatization with tris(2,6-dimethoxyphenyl)methyl cation. The activity of fractions against pathogenic microbes has been studied. The results allow the supposition that the INA-5812 antibiotic complex is a glyco- or lipoglycopeptide antibiotic of a new type, which is very promising for further study. © 2016, Pleiades Publishing, Ltd

Investigation of the complex antibiotic INA-5812

A concentrate with the antimicrobial activity has been isolated from the culture broth of Streptomyces roseoflavus INA-Ac-5812. Its further fractionation by reversed-phase HPLC has resulted in six fractions. It has been established by MALDI-TOF and ESI-MSn precision mass-spectrometry methods that the main components of the complex antibiotic are several closely related compounds, presumably of a glycopeptide nature. The fraction containing an individual component with a mass of 1845.788 Da has been characterized by UV/Vis absorbance and fluorescence spectra, amino acid analysis, and derivatization with tris(2,6-dimethoxyphenyl)methyl cation. The activity of fractions against pathogenic microbes has been studied. The results allow the supposition that the INA-5812 antibiotic complex is a glyco- or lipoglycopeptide antibiotic of a new type, which is very promising for further study. © 2016, Pleiades Publishing, Ltd