Properties and uses of protein hydrolysates (Review)

Properties of protein hydrolysates and possible uses of these substances in research and various branches of industry are considered. The main problem discussed in this paper is the relationship between the degree of protein conversion and characteristics (structural-functional and physicochemical) of hydrolysates.     

Hydrolase from Xanthomonas rubrilineans for synthesis of cefalexin

The use of peptide hydrolase (EC 3.4.13.1) from Xanthomonas rubrilineans for synthesis of the antibiotic cephalexin from 7-aminodesacetoxycephalosporanic acid was studied. The optimum conditions for production of cephalexin were determined, and the yield exceeded 80%. A method for monitoring the synthesis of this antibiotic synthesis by means of a conventional amino acid analyzer is proposed.     

Intensification of composting processes by aerobic microorganisms: A review

Microbiological and biotechnological characteristics of intensification of aerobic processing of organic waste have been reviewed, with a view for revealing two types of correlations: (1) between the quality of the composts obtained and the microorganisms involved in composting and (2) between physicochemical parameters and consumer properties of the composts.     

Membrane-proximal external HIV-1 gp41 motif adapted for destabilizing the highly rigid viral envelope

Electron microscopy structural determinations suggest that the membrane-proximal external region (MPER) of glycoprotein 41 (gp41) may associate with the HIV-1 membrane interface. It is further proposed that MPER-induced disruption and/or deformation of the lipid bilayer ensue during viral fusion. However, it is predicted that the cholesterol content of this membrane (∼45 mol %) will act against MPER binding and restructuring activity, in agreement with alternative structural models proposing that the MPER constitutes a gp41 ectodomain component that does not insert into the viral membrane. Here, using MPER-based peptides, we test the hypothesis that cholesterol impedes the membrane association and destabilizing activities of this gp41 domain. To that end, partitioning and leakage assays carried out in lipid vesicles were combined with x-ray reflectivity and grazing-incidence diffraction studies of monolayers. CpreTM, a peptide combining the carboxyterminal MPER sequence with aminoterminal residues of the transmembrane domain, bound and destabilized effectively cholesterol-enriched membranes. Accordingly, virion incubation with this peptide inhibited cell infection potently but nonspecifically. Thus, CpreTM seems to mimic the envelope-perturbing function of the MPER domain and displays antiviral activity. As such, we infer that CpreTM bound to cholesterol-enriched membranes would represent a relevant target for anti-HIV-1 immunogen and inhibitor development.     

Collagen fractions, obtained by water-salt extraction from animal fats

Collagen fractions have been isolated by water-salt extraction from raw materials of animal origin (various tendon types or subcutaneous tissues of cattle, or porcine skin). Collagen fractions with maximum capacity for water and fat retention were isolated with high efficiency by water-salt solutions containing 1-10% sodium chloride at temperatures below 50 degrees C. The values of the effective constant of extraction rate (min-1) at pH 6.5, 9.0, and 12.0 were equal to (2.7 +/- 0.1) x 10(-3), (6.2 +/- 0.5) x 10(-3), and (15.4 +/- 0.7) x 10(-3), respectively. The optimum conditions found made it possible to isolate collagen those proteinaceous fractions that are of practical use in food industry.     

Proteolytic activity of the enzyme complex of the mammalian pancreas in comparison with pancreatin

The proteolytic activity and thermal stability of the enzyme complex of cell suspension from pig and bovine pancreas glands was compared with those of pancreatin. The enzyme complex displayed the highest thermal stability and activity at 50 degrees C. The kinetic constants, energies of activation and inactivation of the enzyme complex, and pH optimum (7.0 +/- 0.1) at which this complex had the maximum proteolytic activity were determined. Pancreatin had a pH optimum of 8.0 +/- 0.1.     

Kinetic characteristics of enzymatic hydrolysis of complex protein substrates for preparing culture media

Hydrolysis of a protein mixture from muscle and bone tissues with the enzymatic system from procine pancreatic cell suspension was studied. Kinetic constants and the values of activation energy were determined for individual processes of the release of 15 amino acids. The kinetic characteristics of the overall enzymatic hydrolysis calculated from analysis of the changes in concentrations of terminal amino groups were compared with the characteristics obtained while studying the accumulation patterns of individual amino acids.     

A cephalexin-synthesizing hydrolase fromXanthomonas rubrilineans

The use of peptide hydrolase (EC 3.4.13.1) fromXanthomonas rubrilineans for synthesis of the antibiotic cephalexin from 7-aminodesacetoxycephalosporanic acid was studied. The optimum conditions for production of cephalexin were determined, and the yield exceeded 80%. A method for monitoring the synthesis of this antibiotic by means of a conventional amino acid analyzer is proposed.