Ostensible enzyme promiscuity: alkene cleavage by peroxidases

Area of Science:

• Biochemistry
• Enzymology
• Chemical Catalysis

Background:

• Enzyme promiscuity describes an enzyme's ability to catalyze reactions beyond its primary function.
• Peroxidases are known for their role in oxidation reactions.

Purpose of the Study:

• To investigate an alternate catalytic activity of peroxidases.
• To define and characterize a specific type of enzyme promiscuity.

Main Methods:

• Enzymatic assays using peroxidases and selected substrates.
• Comparative analysis with hemin chloride.
• Investigation of the role of the enzyme's peptide backbone and prosthetic group.

Main Results:

• Peroxidases catalyze the cleavage of C=C double bonds adjacent to aromatic moieties.
• This activity is dependent on the hemin prosthetic group, not the peptide backbone.
• The reaction rate with peroxidase is comparable to that with hemin chloride alone.

Conclusions:

• A new term, "ostensible enzyme promiscuity," is proposed for activities traceable to a single catalytic site.
• This promiscuous activity can occur independently of the enzyme's peptide backbone.
• The prosthetic group (hemin) is sufficient for catalyzing this specific reaction.