Tryptophanase in diverse bacterial species.

The distribution of tryptophanase was studied. The highest observed specific activity, mumoles per minute per milligram (dry weight) cells, is given in parentheses after each species. Tryptophanase was inducible and repressible in Escherichia coli (.914), Paracolobactrum coliforme (.210), Proteus vulgaris (.146), Aeromonas liquefaciens (.030), Photobacterium harveyi (.035), Sphaerophorus varius (.021), Bacteroides sp. (.048), and Corynebacterium acnes (.042). The enzyme was constitutive and nonrepressible in Bacillus alvei (.013), and was inducible but not repressible by glucose in Micrococcus aerogenes (.036). Indole-positive bacteria were found in fecal or intestinal samples from a variety of animals among the mammals, reptiles, insects, molluscs, fish, crustaceans, and amphibians.