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Hybrid protein, cancer necrosis factor thymosin-alpha1 (CNF-T), when synthesizing in strain-producer of Escherichia coli SG200-50 with plasmid pThy315, was a part of "inclusion bodies" mostly in the form of a high-molecular complex with other proteins due to the S-S bonds formation. An approach of purification of CNF-T has been proposed, which is based on the destruction of the complex in the presence of sodium dodecylsulfate (DDS-NA) and dithiotreitol (DDT) followed by gel-filtration on Sephadex G-100 and renaturation by ultrafiltration on hollow fibers. The method allows the isolation of electrophoretically homogeneous CNF-T containing no DDS-Na and having high cytotoxic activity against cancer cells of mouse adenocarcinome L-929. The yield of CNF-T achieved 80% relative its content in biomass and 30% relative the total protein.

The active site of lysostaphin is shown to contain a residue of glutamic acid. As judged by a pK value of 9.2 (with pentaglycine bridges in peptidoglycan of staphylococci as a substrate), another ionogenic residue could be the epsilon-amino group of a lysine. However, the pH value near a negatively charged cell is supposed to be strongly shifted to acidity as compared to the pH of the solution volume. This shifts the enzyme pH dependence curve in solution to alkalinity. Therefore, the other group might be histidine, which is consistent with the X-ray crystallographic data. A similar shift is likely to occur for lysozyme in the case of Micrococcus lysodeikticus cells. Determination of pK of ionogenic groups in the active sites of alkaline enzymes responsible for lysis of negatively charged bacterial cells gives their apparent values because the "pericellular" and "voluminous" values of pH are not coincident.

The rate of lysostaphin-catalyzed lysis of staphylococci follows the Michaelis-Menten equation at [E](0) << [S](0), i.e., the activity of the enzyme is proportional to its concentration. This equation is proposed for determining the specific activity of lysostaphin. The apparent activation energy of hydrolysis of pentaglycine bridges in Staphylococcus peptidoglycan is 77.9 kJ/mol.

This work presents a method for purification of lysostaphin, a glycylglycine endopeptidase, from the culture liquid of S. simulans biovar staphylolyticus to homogeneity in a few steps. The method includes ultrafiltration and ion-exchange and hydrophobic chromatographies. The enzyme was isolated in preparative amounts with the yield of 51%. Some physical and chemical properties of the enzyme are described.

Some pathogenic bacteria have been demonstrated to secrete specific IgA1-proteases, the enzymes cleaving the molecules of the first subclass of human immunoglobulin (IgA1) in the single point from the hinge with the formation of Fab- and Fc-fragments. Cleavage generally deprives immunoglobulins having defense properties and the enzymes are considered as pathogenic factors. How to determine the activity, purification, and the promises of use of IgA-proteases is described. Whether inactivated meningococcal IgA1-protease as a vaccine against any of the five (A, B, C, Y, W135) serotypes of pathogenic meningococci is discussed.