Which genera are positive for phenylalanine deaminase?

Which genera are positive for phenylalanine deaminase?

• A. Enterobacter, Escherichia, and Salmonella
• B. Morganella, Providencia, and Proteus
• C. Klebsiella and Enterobacter
• D. Proteus, Escherichia, and Shigella

Answer: (B)

Phenylalanine deaminase (PAD) is an enzyme that certain bacteria produce, allowing them to convert phenylalanine to phenylpyruvic acid. The genera that are known to test positive for PAD are typically associated with specific metabolic pathways that involve the breakdown of amino acids. Morganella, Providencia, and Proteus are significant within the Enterobacteriaceae family for their ability to produce phenylalanine deaminase. This ability is a key differentiating biochemical characteristic that aids in identifying and classifying these organisms in microbiological settings. The enzyme production can be detected using specific agar media, such as phenylalanine agar, which will yield a color change in the presence of the phenylpyruvic acid. The other choices include genera that generally do not produce phenylalanine deaminase. For instance, Enterobacter and Escherichia, while important members of the Enterobacteriaceae family, typically do not possess this enzymatic activity, and Klebsiella is similarly known to be negative for PAD. Thus, the identification of Morganella, Providencia, and Proteus as positive for phenylalanine deaminase is a widely accepted standard in microbiology, confirming the accuracy of

Phenylalanine deaminase (PAD) is an enzyme that certain bacteria produce, allowing them to convert phenylalanine to phenylpyruvic acid. The genera that are known to test positive for PAD are typically associated with specific metabolic pathways that involve the breakdown of amino acids.

Morganella, Providencia, and Proteus are significant within the Enterobacteriaceae family for their ability to produce phenylalanine deaminase. This ability is a key differentiating biochemical characteristic that aids in identifying and classifying these organisms in microbiological settings. The enzyme production can be detected using specific agar media, such as phenylalanine agar, which will yield a color change in the presence of the phenylpyruvic acid.

The other choices include genera that generally do not produce phenylalanine deaminase. For instance, Enterobacter and Escherichia, while important members of the Enterobacteriaceae family, typically do not possess this enzymatic activity, and Klebsiella is similarly known to be negative for PAD. Thus, the identification of Morganella, Providencia, and Proteus as positive for phenylalanine deaminase is a widely accepted standard in microbiology, confirming the accuracy of