pubmed:abstractText |
Escherichia coli mutants defective in protease III were isolated by enzyme assays of heavily mutagenized colones. One mutant produced thermolabile enzyme, and it is presumed to have a mutation in the structural gene of protease III. Two other mutants mapping at the same site had less than 5% of the wild-type protease III level. The genetic locus of these mutations, designated ptr, was located at approximately 60 min on the E. coli linkage map based on its high frequency (70%) of contransduction by P1 with argA. Strains with less than 5% of the wild-type protease III activity grew normally and degraded nonsense fragments of beta-galactosidase at wild-type rates.
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