[Stability of normal, abnormal and recombinant proteins in Escherichia coli strains deficient for intracellular proteinase La--the product of the lon gene]. / Izuchenie stabil'nosti normal'nykh, anomal'nykh i genno-inzhenernykh belkov v shtammakh Escherichia coli, defitsitnykh po vnutrikletochnoi proteinaze La--produkte gena lon.

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. The rate of degradation of canavanine-containing abnormal proteins, as well as foreign proteins was significantly higher in E. coli than that of normal proteins. Lon-mutants possessed 2-2.5-fold lower rates of degradation of abnormal proteins as compared with Lon+-strains. The rate of degradation of human interferon alpha-2 was 10-fold higher in E. coli than that of abnormal proteins. B. amyloliquefaciens alpha-amylase degraded in E. coli with the rate comparable with that of abnormal proteins, since chloramphenicolacetyltransferase from Tn9 was stable in E. coli. The rate of degradation of interferon alpha-2 was 2-fold lower in Lon-mutants (half-life 23-26 min) than in the initial strain (11-12 min). Lon-mutants were effectively used as recipient strains for constructing strains-producers of several human alpha- and beta-interferons.

[Isolation and properties of human leukocyte interferon obtained by microbial synthesis]. / Vydelenie i svoistva chelovecheskogo leikotsitarnogo interferona, poluchennogo mikrobnym sintezom.

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. These amounts were sufficient for the interferon structural and physico-chemical analysis. The isolated interferons are characterized by high stability on storage and may serve a basis for preparation of pharmaceutical agents.

[Limited proteolysis of human leukocyte interferon-alpha2 and localization of the antigenic determinant binding the monoclonal antibodies]. / Ogranichennyi proteoliz chelovecheskogo leikotsitarnogo interferona-alpha2 i lokalizatsiia antigennoi determinanty, sviazyvaiushchei monoklonal'nye antitela.

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. INF-alpha 2 fragments 1-139, 1-147, 1-149 are capable of binding antibodies, whereas fragments 1-109 and 1-112 do not bind antibodies NK2. A comparison of the primary structure of human leucocyte and murine leucocyte INF families in the region of sequence 110-139 and an analysis of the ability of human INF differing in amino acid sequences to bind antibodies NK2 demonstrated that the antigenic determinant for antibodies NK2 is the sequence Glu114-Asp115-Ser116-Ile117 of the INF-alpha 2 molecule.