New mutants of escherichia coli, which are capable of excrete in the extracellular medium of a protein periplasmic, their preparation and their application for the preparation of beta - lactamases, or of a protein hybrid beta - lactamases

摘要

Mutants of escherichia coli, which are capable of excrete in the extracellular medium of a protein periplasmic, characterized by the fact that they are derived from a parent strain capable of synthesize a beta - e.g. lactamase or a hybrid protein comprising a sequence of amino - terminal similar to that of the beta - e.g. lactamase, the parent strain does not excreting protein periplasmic including beta - e.g. lactamase or said hybrid protein, or by excreting not more than 5 was 30c, that these mutants are carriers of a mutation cotransductible has more than 50 with the marker gal, whether they are, as the parent strain, which is not sensitive to one or several growth inhibitors chosen from among the acid cholic, the chloramphenicol and edta, whether they are sensitive, such as the parent strain, a colicin e 1, that, as the parent strain, they do not excrete alkaline phosphatase or in excrete not more than 20 a, 30c, and that they excrete at least 50 of the beta - e.g. lactamase (or of the hybrid protein) that they produce a 37c, as well as their preparation. / p & & p & application in particular for the production of beta - lactamases.