Aryl acylamidase from Rhodococcus erythropolis NCIB 12273

Area of Science:

• Microbiology
• Biochemistry
• Enzyme kinetics

Background:

• Acetaminophen is a common analgesic and antipyretic.
• Microbial degradation pathways for pharmaceuticals are crucial for environmental remediation.
• Understanding drug metabolism by microorganisms can reveal novel enzymatic activities.

Purpose of the Study:

• To isolate and characterize microorganisms capable of utilizing acetaminophen as a sole carbon and energy source.
• To investigate the enzymatic activity responsible for acetaminophen degradation.
• To assess the potential of the isolated enzyme for clinical diagnostic applications.

Main Methods:

• Isolation of soil microorganisms on selective media with acetaminophen.
• Cultivation of bacteria in the presence of an anilide inducer.
• Partial purification of the aryl acylamidase enzyme using ion exchange and hydrophobic interaction chromatography.
• Enzyme activity assays, including electrochemical methods, and determination of kinetic parameters (Km).

Main Results:

• A Rhodococcus erythropolis strain was identified that grows using acetaminophen.
• The bacterium expresses aryl acylamidase (EC 3.5.1.13) activity, induced by anilides.
• Enzyme activity is not repressed by common growth medium constituents.
• The enzyme efficiently converts acetaminophen to aniline with a Km of 0.11 mM at pH 8.0.

Conclusions:

• Rhodococcus erythropolis possesses a robust aryl acylamidase capable of acetaminophen metabolism.
• The enzyme's stability and activity profile suggest its suitability for diagnostic reagent development.
• This finding opens avenues for microbial acetaminophen detection methods.