What Is 2-dehydropantoate aldolase

Content on WhatAnswers is provided "as is" for informational purposes. While we strive for accuracy, we make no guarantees. Content is AI-assisted and should not be used as professional advice.

Last updated: April 15, 2026

Quick Answer: 2-dehydropantoate aldolase is an enzyme classified under EC 4.1.3.37 that catalyzes the reversible cleavage of 2-dehydropantoate into alanine and 2-oxopropanal. It plays a critical role in coenzyme A biosynthesis and is found in bacteria, plants, and some archaea.

Key Facts

2-dehydropantoate aldolase is assigned the Enzyme Commission (EC) number 4.1.3.37
The enzyme catalyzes a reversible reaction in the pantothenate (vitamin B5) biosynthesis pathway
It was first characterized in Escherichia coli in the 1970s
The reaction involves cleavage of 2-dehydropantoate into L-alanine and 2-oxopropanal
The enzyme requires no cofactors, operating efficiently under physiological pH and temperature

Overview

2-dehydropantoate aldolase is a key enzyme in the biosynthesis of pantothenate, the precursor to coenzyme A (CoA), an essential cofactor in central metabolism. This enzyme catalyzes the reversible aldol cleavage of 2-dehydropantoate into L-alanine and 2-oxopropanal, a reaction critical for microbial and plant metabolic pathways.

Found primarily in bacteria, archaea, and plant plastids, 2-dehydropantoate aldolase operates without the need for metal ions or organic cofactors. Its activity supports the de novo synthesis of vitamin B5, making it a target for antimicrobial drug development due to its absence in humans.

EC number: The enzyme is officially classified as EC 4.1.3.37 by the International Union of Biochemistry and Molecular Biology (IUBMB).
Substrate specificity: It acts specifically on (R)-2-dehydropantoate, showing high stereoselectivity for its natural substrate.
Molecular weight: In Escherichia coli, the enzyme has a subunit mass of approximately 23 kDa and functions as a homodimer.
Gene name: In bacteria like E. coli, it is encoded by the panE gene, part of the pantothenate biosynthesis operon.
Reaction equilibrium: The reaction favors cleavage, but under cellular conditions, the synthesis direction is driven by downstream metabolism.

How It Works

The mechanism of 2-dehydropantoate aldolase involves a classic type I aldolase mechanism, utilizing a lysine residue to form a Schiff base intermediate with the substrate. This enables carbon-carbon bond cleavage through stabilization of the enamine intermediate.

Schiff base formation: A conserved lysine residue at the active site forms a covalent bond with the carbonyl group of 2-dehydropantoate, initiating catalysis.
Carbon-carbon cleavage: The enzyme facilitates the reversible cleavage of the substrate into L-alanine and 2-oxopropanal, a key step in pantothenate recycling.
pH optimum: Activity peaks between pH 7.5 and 8.5, consistent with physiological conditions in bacterial cytoplasm.
Temperature sensitivity: Maximum activity occurs at 37°C in mesophilic organisms like E. coli, with sharp decline above 45°C.
Kinetic constants: The Km for 2-dehydropantoate is approximately 0.15 mM, indicating high substrate affinity.
Inhibition profile: The enzyme is competitively inhibited by substrate analogs such as ethyl 2-oxopantoate, useful in enzyme mechanism studies.

Comparison at a Glance

Below is a comparison of 2-dehydropantoate aldolase with related aldolases in metabolic pathways:

Enzyme	EC Number	Reaction	Organisms	Cofactor Requirement
2-dehydropantoate aldolase	4.1.3.37	Cleaves 2-dehydropantoate to alanine + 2-oxopropanal	Bacteria, plants, archaea	None
Fructose-1,6-bisphosphate aldolase	4.1.2.13	Glycolysis: splits fructose-1,6-BP into trioses	Universal	None (class I) or Zn²⁺ (class II)
Transketolase	2.2.1.1	Pentose phosphate pathway: transfers glycolaldehyde	Eukaryotes, bacteria	Thiamine pyrophosphate
DAHP synthase	4.1.2.15	Shikimate pathway: condenses PEP + E4P	Plants, bacteria	Mn²⁺ or Co²⁺
Neuraminic acid aldolase	4.1.3.3	Cleaves sialic acids into ManNAc and pyruvate	Animals, bacteria	None

This comparison highlights the unique cofactor independence and metabolic niche of 2-dehydropantoate aldolase. Unlike many aldolases involved in central carbon metabolism, it operates specifically in vitamin biosynthesis, making it a selective target for antibiotic development.

Why It Matters

Understanding 2-dehydropantoate aldolase has significant implications for biotechnology, medicine, and evolutionary biology. As humans lack this enzyme, it represents a promising target for species-specific antimicrobial agents.

Antibiotic development: Inhibitors of PanE could lead to novel antibiotics with minimal off-target effects in humans.
Metabolic engineering: Engineered E. coli strains with modified panE expression increase pantothenate yields for industrial vitamin production.
Herbicide targets: Plants use this pathway, so selective inhibitors could serve as eco-friendly herbicides.
Diagnostic markers: Presence of panE gene helps identify pantothenate-auxotrophic pathogens in clinical microbiology.
Evolutionary insight: The enzyme’s distribution across domains suggests horizontal gene transfer events in microbial evolution.
Bioremediation potential: Some archaeal variants function in extreme conditions, useful in industrial biocatalysis.

Continued research into 2-dehydropantoate aldolase enhances our ability to manipulate metabolic networks for health and industrial applications, underscoring its biochemical and practical importance.