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Enzymatic Cascade Reactions for the Synthesis of Chiral Amino Alcohols from L-lysine
Published on: February 16, 2018
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Enzymatic Cascade Reactions in Biosynthesis.
Christopher T Walsh1, Bradley S Moore2,3
1Stanford University Chemistry, Engineering, and Medicine for Human Health (CheM-H), Stanford University, Stanford, CA, 94305, USA.
Angewandte Chemie (International Ed. in English)
|August 30, 2018
Summary
Enzymes catalyze cascade reactions using nucleophilic, electrophilic, pericyclic, and radical mechanisms. Radical cascades are initiated by oxygen-dependent iron enzymes or anaerobic radical SAM enzymes.
Area of Science:
- Biochemistry
- Organic Chemistry
- Enzymology
Background:
- Enzyme-catalyzed cascade reactions are fundamental to biosynthesis.
- Synthetic chemists categorize cascade reactions mechanistically.
- A unified understanding of enzymatic and synthetic cascade chemistry is needed.
Purpose of the Study:
- To compare enzymatic cascade reactions with synthetic mechanistic categorizations.
- To delineate common underlying chemical principles.
- To categorize enzymatic radical cascade initiation.
Main Methods:
- Review and analysis of known enzyme-catalyzed cascade reactions.
- Classification based on reaction mechanisms (nucleophilic, electrophilic, pericyclic, radical).
- Focus on radical cascade initiation by oxygen-dependent and anaerobic enzymes.
Main Results:
- Identified four mechanistic categories for enzymatic cascades.
- Described two distinct enzyme classes generating radical cascades.
- Characterized iron-based "thwarted oxygenases" using O2 for C-H bond homolysis.
- Characterized radical SAM enzymes using S-adenosylmethionine for C-H bond homolysis.
Conclusions:
- Enzymatic cascades can be classified by mechanistic parallels to synthetic chemistry.
- Radical cascade initiation by enzymes occurs via distinct oxygen-dependent and anaerobic pathways.
- This classification provides a framework for understanding diverse enzyme functions.
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