Ability of Pseudomonas sp. to synthesize aminopeptidases in the presence of various carbon and nitrogen sources

A soil strain of Pseudomonas sp. is able to synthesize at least two aminopeptidases exhibiting high activity in the presence of Phe-beta-NA and Ala-beta-NA as substrates. Irrespective of the used substrate, total activity of studied enzymes was strongly related to concentrations of organic components (peptone, glutamic acid, glucose) in mineral media and was the higher, the higher the concentration. Tendency of changes in total activity was similar for alanyl- and phenylalanylaminopeptidase though their response to different concentrations of organic components was different. Specific activity measured in the presence of Phe-beta-NA and Ala-beta-NA as the substrates was not strictly dependent on increasing concentrations of organic components in the media. The highest specific activity of aminopeptidase was obtained in the presence of Phe-beta-NA as a substrate on the fifth day of culture in medium containing 1% glucose. The obtained results seem to indicate the inductive character of the studied aminopeptidases. On the other hand, however, they do not exclude other regulatory mechanisms of their synthesis, including catabolic repression.