Features and application potential of microbial urethanases

Area of Science:

• Biochemistry
• Enzymology
• Food Safety

Background:

• Ethyl carbamate (EC) is a Group 2A carcinogen found in various foods and alcoholic beverages.
• Currently, no commercial urethanase enzyme is available for EC degradation.
• Urethanase (EC 3.5.1.75) is known to reduce EC, with intracellular presence in yeast, fungi, and bacteria.

Purpose of the Study:

• To review recent advancements in urethanase sequence analysis.
• To explore the potential of identified urethanase enzymes for degrading ethyl carbamate and other carcinogens.
• To highlight the conserved features and activities of urethanase enzymes.

Main Methods:

• Sequence analysis of newly identified urethanase enzymes.
• Comparison of conserved sequences and molecular masses.
• Assessment of enzymatic activity, including amidase and acrylamide degradation.

Main Results:

• Five urethanase enzymes with conserved amidase signature sequences (52-62 kDa) were identified.
• Urethanases from Candida parapsilosis and Aspergillus oryzae form homotetramers; Rhodococcus equi strain TB-60 enzyme is a monomer.
• Enzymes showed amidase activity, with C. parapsilosis and A. oryzae enzymes also degrading acrylamide.

Conclusions:

• Urethanase enzymes possess conserved catalytic triad residues and exhibit amidase activity.
• Identified urethanases can degrade both ethyl carbamate and acrylamide, both Group 2A carcinogens.
• Elucidated urethanase sequences pave the way for developing new enzymes for practical applications in food safety.