Ein neues Verfahren zum direkten Nachweis mikrobieller Aminoacylaseaktivität auf Agarplatten mit o-Phthalaldehyd / A New Detection Procedure for Aminoacylase Activity of Microorganisms Directly on Plate Culture with o-Phthalaldehyde

Not less than 1 nmol of methionine and phenylalanine were detected as fluorescent spots on agar plates with ophthalaldehyde reagent under UV light. Microorganisms were grown on thin- agar-layer coated filter papers placed on nutrient agar plates, and then transfered onto new plates lacking nutrients by moving the papers. After the background amino compounds were removed by the diffusion to the bottom plates, the paper cultures were moved and incubated on assay plates containing N-acetylmethionine or N-acetylphenylalanine. The amino acids formed around the colonies were visualized by the ophthalaldehyde procedure to indicate aminoacylase activity of microorganisms. The substrate- and stereospecificity of the enzyme was shown for some strains on the agar plates by this procedure.