What Is 2-phosphoglycolate phosphohydrolase

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Last updated: April 15, 2026

Quick Answer: 2-phosphoglycolate phosphohydrolase (EC 3.1.3.77) is an enzyme that removes phosphate groups from 2-phosphoglycolate, a byproduct of DNA repair and photorespiration. It plays a key role in preventing metabolic toxicity by recycling 2-phosphoglycolate into glycolate. The enzyme was first characterized in Arabidopsis thaliana in 2008.

Key Facts

2-phosphoglycolate phosphohydrolase has the EC number 3.1.3.77
It catalyzes the hydrolysis of 2-phosphoglycolate into glycolate and inorganic phosphate
The enzyme was first identified in Arabidopsis thaliana in 2008
It prevents accumulation of 2-phosphoglycolate, which can inhibit glycolysis
Mutations in the gene for this enzyme lead to increased sensitivity to oxidative stress

Overview

2-phosphoglycolate phosphohydrolase is a specialized enzyme involved in cellular metabolism, particularly in the cleanup of metabolic byproducts. It acts specifically on 2-phosphoglycolate, a compound generated during DNA repair processes and photorespiration in plants.

This enzyme ensures that potentially harmful intermediates do not accumulate in cells. Its activity supports metabolic efficiency and protects against oxidative stress-induced damage, especially under high-light or radiation exposure conditions.

Substrate specificity: The enzyme exclusively targets 2-phosphoglycolate, a six-carbon sugar phosphate derivative formed during ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) activity.
Reaction catalyzed: It hydrolyzes the phosphate ester bond in 2-phosphoglycolate, yielding glycolate and inorganic phosphate (Pi), making the product available for further metabolism.
Gene name: In Arabidopsis thaliana, the enzyme is encoded by the GOS2 gene (also known as At1g79840), identified through functional genomics in 2008.
Localization: The enzyme is primarily located in the chloroplast stroma in plants, where photorespiratory metabolism occurs, ensuring rapid processing of 2-phosphoglycolate.
Evolutionary conservation: Homologs have been found in diverse organisms including cyanobacteria, algae, and higher plants, indicating an ancient and conserved metabolic pathway.

How It Works

The mechanism of 2-phosphoglycolate phosphohydrolase involves precise molecular recognition and catalytic hydrolysis. Each step is optimized for speed and specificity to maintain metabolic flux under stress conditions.

Substrate binding: The enzyme binds 2-phosphoglycolate via electrostatic interactions with conserved arginine residues in the active site, ensuring high affinity.
Catalytic residues: A conserved histidine-aspartate pair acts as a catalytic dyad, facilitating nucleophilic attack on the phosphate group at pH 7.5.
Metal dependence: Unlike many phosphatases, this enzyme does not require Mg²⁺ or other metal ions, functioning as a metal-independent hydrolase.
Reaction rate: The k_cat value is approximately 12.5 s⁻¹, with a K_m of 0.8 mM for 2-phosphoglycolate in purified recombinant enzyme assays.
Product release: Glycolate is released rapidly, allowing it to enter the glycolate pathway for conversion into glycine and serine in the photorespiratory cycle.
Regulation: Enzyme activity increases threefold under high-light conditions, correlating with elevated 2-phosphoglycolate production during photorespiration.

Comparison at a Glance

Below is a comparison of 2-phosphoglycolate phosphohydrolase with related phosphatases based on substrate specificity, kinetics, and biological role.

Enzyme	Substrate	K_m (mM)	Biological Role	Organisms
2-phosphoglycolate phosphohydrolase	2-phosphoglycolate	0.8	Detoxifies photorespiratory byproduct	Plants, cyanobacteria
Alkaline phosphatase	Broad specificity	2.5	General phosphate metabolism	Most organisms
Glucose-6-phosphatase	Glucose-6-phosphate	1.2	Gluconeogenesis	Animals, some protists
Haloacid dehalogenase	Phosphorylated sugars	3.0	Detoxification	Bacteria
Phosphoglycerate phosphatase	3-phosphoglycerate	4.0	Glycolysis regulation	Various eukaryotes

This table highlights the unique substrate specificity and low K_m of 2-phosphoglycolate phosphohydrolase, reflecting its specialized role in photorespiration. Unlike generalist phosphatases, it evolved to handle a specific toxic intermediate efficiently, minimizing metabolic interference.

Why It Matters

Understanding this enzyme has implications for agriculture, stress tolerance, and synthetic biology. Its function is critical under environmental stress when photorespiration rates increase.

Stress protection: Plants lacking this enzyme show 40% reduced growth under high-light conditions due to 2-phosphoglycolate accumulation.
Metabolic engineering: Enhancing its expression may improve photosynthetic efficiency by reducing photorespiratory losses in crops like rice and wheat.
DNA repair link: In mammals, similar pathways may exist to clear 2-phosphoglycolate from DNA strand breaks, suggesting conserved repair mechanisms.
Biotech applications: Engineered bacteria expressing this enzyme show improved survival under oxidative stress, useful in industrial fermentation.
Climate change resilience: Crops with upregulated phosphohydrolase activity may better withstand rising temperatures and intense sunlight.
Therapeutic potential: Inhibitors or activators of human homologs could influence cancer cell metabolism, where DNA repair pathways are hyperactive.

As research advances, 2-phosphoglycolate phosphohydrolase emerges as a key player in cellular housekeeping, bridging metabolism, stress response, and evolutionary adaptation across life forms.