抄録
A mutant, strain M-6, capable of utilizing taurocyamine (2-guanidinoethanesulfonate) as a nitrogen source was isolated from the parent strain, Pseudomonas aeruginosa GB-4, a derivative of wild-type P. aeruginosa PAO1 lacking the ability to produce guanidinobutyrase (EC 3.5.3.7). 3-Guanidinopropionate amidinohydrolase (EC class 3.5.3), which acts slowly on taurocyamine, was induced effectively by only 3-guanidinopropionate in the parent strain, while the enzyme of strain M-6 was induced by taurocyanime, guanidinoacetate, 3-guanidinopropionate, 4-guanidinobutyrate, and guanidinosuccinate. Strain M-6 synthesized a slight amount of the enzyme constitutively. The enzyme partially purified from strain M-6 exhibited substrate specificity similar to that of the wild-type strain. The mutant could grow also on 4-guanidinobutyrate, unlike the parent strain. These results indicate that strain M-6 acquired the ability to grow on taurocyamine by virtue of a mutation at the regulatory gene for 3-guanidinopropionate amidinohydrolase, which led to alteration of the specificity of the regulatory protein.
