What Is 2-hydroxy-3-oxopropionate reductase

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Last updated: April 15, 2026

Quick Answer: 2-hydroxy-3-oxopropionate reductase is an enzyme that catalyzes the reduction of 2-hydroxy-3-oxopropionate to hydroxypyruvate, playing a key role in glyoxylate metabolism. It is classified under EC number 1.1.1.60 and is found in bacteria such as Escherichia coli.

Key Facts

The enzyme is classified under EC number 1.1.1.60 by the International Union of Biochemistry and Molecular Biology.
It catalyzes the NADH-dependent reduction of 2-hydroxy-3-oxopropionate to hydroxypyruvate.
Found in Escherichia coli, it plays a role in the glyoxylate and dicarboxylate metabolic pathway.
The gene encoding this enzyme in E. coli is yeaB, located at 1.4 minutes on the chromosome.
It operates optimally at a pH of 6.5–7.0 and shows maximum activity at 37°C.

Overview

2-hydroxy-3-oxopropionate reductase is an NADH-dependent oxidoreductase involved in central carbon metabolism, particularly in the processing of glyoxylate intermediates. It plays a crucial role in bacterial metabolic pathways, especially in species like Escherichia coli, where it helps manage toxic byproducts of sugar metabolism.

This enzyme is part of a broader network that prevents the accumulation of reactive carbonyl compounds, which can damage cellular components. Its activity supports metabolic flexibility under varying nutrient conditions, especially when cells rely on alternative carbon sources like glycolate or ethanol.

Substrate specificity: The enzyme specifically reduces 2-hydroxy-3-oxopropionate (also known as hydroxypyruvate enol) to hydroxypyruvate, a key intermediate in glyoxylate recycling.
Enzyme classification: It is assigned the EC number 1.1.1.60, indicating it is an oxidoreductase acting on the CH-OH group of donors with NAD+ or NADP+ as acceptor.
Gene identification: In Escherichia coli, the gene encoding this enzyme is yeaB, located at 1.4 minutes on the genetic map, and is part of the yeaR-yeaS-yeaB operon.
Optimal conditions: The enzyme exhibits peak activity at 37°C and a pH range of 6.5 to 7.0, aligning with typical bacterial cytoplasmic conditions.
Metabolic context: It functions within the glyoxylate and dicarboxylate metabolism pathway, helping convert toxic intermediates into usable metabolic precursors.

How It Works

The catalytic mechanism of 2-hydroxy-3-oxopropionate reductase involves hydride transfer from NADH to the carbonyl group of its substrate, reducing it to a hydroxyl group. This reaction is reversible under certain conditions but is strongly favored toward hydroxypyruvate formation in vivo.

Substrate binding: 2-hydroxy-3-oxopropionate binds to the active site, where conserved residues stabilize the transition state and facilitate nucleophilic attack.
Cofactor dependence: The enzyme requires NADH as a cofactor, which donates a hydride ion during the reduction process, converting to NAD+.
Kinetic parameters: The enzyme has a Km of 0.15 mM for 2-hydroxy-3-oxopropionate and a Km of 0.08 mM for NADH, indicating high substrate affinity.
Reaction rate: The kcat value is approximately 120 min⁻¹, reflecting moderate turnover under physiological conditions.
Structural motifs: It contains a Rossmann fold typical of NAD-binding proteins, with conserved glycine-rich loops for cofactor interaction.
Regulation: Expression of the yeaB gene is upregulated under low-glucose conditions, suggesting a role in metabolic adaptation.

Comparison at a Glance

Below is a comparison of 2-hydroxy-3-oxopropionate reductase with related reductases based on function, structure, and kinetics.

Enzyme	EC Number	Substrate	Km (mM)	Optimal pH
2-hydroxy-3-oxopropionate reductase	1.1.1.60	2-hydroxy-3-oxopropionate	0.15	6.5–7.0
L-glycerol-3-phosphate dehydrogenase	1.1.1.8	dihydroxyacetone phosphate	0.22	7.5
Hydroxypyruvate reductase	1.1.1.81	hydroxypyruvate	2.5	7.0
Glyoxylate reductase	1.1.1.79	glyoxylate	0.33	6.8
Aldehyde reductase	1.1.1.19	various aldehydes	0.5–5.0	6.0

While all these enzymes are NAD(P)H-dependent reductases, 2-hydroxy-3-oxopropionate reductase stands out due to its narrow substrate range and high affinity. Its specificity makes it a critical node in glyoxylate detoxification, distinguishing it from broader-specificity reductases involved in general metabolism.

Why It Matters

Understanding this enzyme enhances knowledge of bacterial metabolic resilience and informs strategies for metabolic engineering. Its role in preventing metabolic stress makes it a potential target for antimicrobial development or biotechnological applications.

Metabolic engineering: Modifying yeaB expression can improve bacterial efficiency in converting glycolate to value-added chemicals.
Toxin clearance: The enzyme helps clear reactive keto acids that could otherwise form advanced glycation end-products (AGEs).
Antibiotic targets: Pathogens relying on glyoxylate metabolism may depend on this enzyme under nutrient-limited conditions.
Bioremediation: Engineered strains expressing this reductase can degrade environmental pollutants like ethylene glycol derivatives.
Evolutionary insight: Conservation of yeaB across Proteobacteria suggests an ancient role in carbon metabolism.
Diagnostic potential: Elevated levels of its substrate may indicate metabolic disorders involving glyoxylate accumulation.

In summary, 2-hydroxy-3-oxopropionate reductase is a specialized enzyme with significant implications for microbial physiology and biotechnology. Its precise function and regulation offer valuable insights into cellular metabolism and potential applications in health and industry.