Using MALDI TOF/TOF mass spectrometry, the sites hydrolysis of proteins by β-lytic metalloproteinase from Lysobacter capsici, strain VKM 2533T bacteria were identified and the molecular specificity of this enzyme was determined. Analysis of the hydrolysis products of eight proteins (myoglobin, three chains of casein, hemoglobin, ovalbumin, ovomucoid, bovine serum albumin, and Drosophila enolase 2) revealed the specificity of Lysobacter capsici β-lytic protease to hydrolyze peptide bonds at the carboxyl groups of glycine, lysine, alanine, phenylalanine, serine, asparagic acid, threonine, valine, glutamic acid, histidine, arginine, and cysteine. The most frequently hydrolyzed amino acids were glycine and alanine, which may be due to their small size and high accessibility to the active center of the enzyme. At the same time, the presence of additional hydrolysis sites, such as threonine, in the hydrolysis of proteins in PAAG, but not in solution, indicates the influence of protein conformation on the availability of certain sites for the enzyme. Comparison of the results of protein hydrolysis in solution and in PAAG showed that protein denaturation during electrophoresis can affect the accessibility of hydrolysis sites. For example, hydrolysis of myoglobin in gel revealed an additional threonine hydrolysis site, which was absent when hydrolyzed in solution. This confirms that protein conformational changes caused by denaturation can significantly affect the specificity of proteolysis.
MALDI mass spectrometry, bacterial metalloprotease, protein hydrolysis, electrophoresis, amino acids
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