OVEREXPRESSION OF BACILLUS-INTERMEDIUS 7P RIBONUCLEASE (BINASE) IN ESCHERICHIA-COLI

We have earlier reported cloning of the chromosomal gene for an alkali ne RNase binase in E. coli. In this work, the approach termed ''homolo gous gene recombination'' was used to construct vectors for binase exp ression in E. coli, directed through the tac promoter of the P-R promo ter of phage lambda under the control of a temperature-sensitive CI857 repressor. The latter promoter provided a maximal yield of binase, up to 100 mg protein per liter of bacterial culture. Placing the termina tor at the 3' end of the gene enhances the enzyme yield at least twofo ld. A chromatographic method was designed and used to monitor binase a ccumulation in the culture medium without an RNase assay.