[Stability of normal, abnormal and recombinant proteins in Escherichia coli strains deficient for intracellular proteinase La--the product of the lon gene].

Escherichia coli Lon-mutants deficient in intracellular protease La have been isolated. The rate of degradation of normal cellular proteins was 1.5-2-fold lower in Lon-mutants as compared with that of the wild type strain.

[Isolation and properties of human leukocyte interferon obtained by microbial synthesis].

Highly sensitive, effective and simple methods for determination of leukocytic interferons were developed. The methods are based on formation of immune complexes of interferon with anti-interferon monoclonal and polyclonal antibodies immobilized on an insoluble basis. As a result of interferon alpha 2 purification from the biomass of the interferon-producing bacteria the preparative amounts of the protein were obtained.

[Limited proteolysis of human leukocyte interferon-alpha2 and localization of the antigenic determinant binding the monoclonal antibodies].

Large peptide fragments of human leucocyte interferon-alpha 2 (INF-alpha 2) were obtained by limited proteolysis with trypsin, pepsin, thermolysine and Bacillus amyloliquefaciens intracellular serine proteinase. The ability of the fragments to bind murine monoclonal antibodies NK2 raised against INF-alpha 2 was studied by the immunoblotting technique. The region of sequence 110-149 is the most sensitive to proteolytic attack, being probably exposed on the surface of the INF-alpha 2 molecule.