Racemization of lysine by a pseudomonad.

The recent paper by Huang and Davisson (J. Bacteriol., 76, 495, 1958) on the distribution of lysine racemase in bacteria reports its occurrence in only a few species of Escherichia and Proteus. Various other bacteria including 22 strains of various genera of the Pseudomonadaceae did not possess such activity. I wish to report evidence for the occurrence of lysine racemase activity in a Pseudomonas sp., which produced the fluorescent pigment typical of many such isolates from soil enrichment cultures. This work was done at the University of California at Los Angeles in 1953 and 1954 but has not been reported previously because circumstances prohibited the completion of the larger planned study on the metabolism of lysine. The specific point which would seem to explain the occurrence of the enzyme in the strain utilized is that it was isolated, by enrichment techniques, for its ability to grow on DL-lysine