Recombinant Human GLUD2 Protein: Properties & Research Guide

Recombinant Human GLUD2 Protein is a mitochondrial enzyme critical for glutamate catabolism and energy metabolism, particularly in neural tissues, and is available from Aladdin Scientific (SKU: rp372297) for use in biochemical, metabolic, and neuroscience research applications.

Gene Name

GLUD2 (Glutamate Dehydrogenase 2)

Protein Type

Recombinant Human Protein

Subcellular Localization

Mitochondrial matrix

Primary Function

Catalyzes the reversible oxidative deamination of glutamate to α-ketoglutarate and ammonia, linking amino acid metabolism to the TCA cycle

Tissue Expression

Predominantly expressed in brain and neural tissues; distinct from the ubiquitous GLUD1 isoform

SKU

rp372297

Supplier

Aladdin Scientific

Biological Background of GLUD2

Glutamate dehydrogenase 2 (GLUD2) is a homotetrameric mitochondrial enzyme encoded by the GLUD2 gene, which arose from a retrotransposition event of the ancestral GLUD1 gene and is found primarily in primates. Unlike the ubiquitously expressed GLUD1, GLUD2 is predominantly expressed in the brain, testes, and retina, reflecting its specialized physiological roles in these tissues.

GLUD2 catalyzes the reversible oxidative deamination of L-glutamate to α-ketoglutarate (2-oxoglutarate) and ammonium, using NAD⁺ or NADP⁺ as cofactors. This reaction links amino acid catabolism directly to the tricarboxylic acid (TCA) cycle, enabling neurons to use glutamate as an energy substrate. GLUD2 is particularly important for maintaining glutamate homeostasis in the central nervous system, where glutamate serves as the primary excitatory neurotransmitter.

The regulatory properties of GLUD2 differ from GLUD1: GLUD2 is less sensitive to inhibition by GTP and shows enhanced activity in the presence of ADP under conditions of high synaptic activity, making it especially suited to sustaining neuronal energy demands during periods of increased neural firing.

Protein Characteristics and Quality Attributes

Recombinant Human GLUD2 Protein (SKU: rp372297) from Aladdin Scientific is produced using recombinant expression systems to ensure consistency, reproducibility, and high purity suitable for in vitro research applications. Researchers should consult the product datasheet for the specific lot-dependent specifications, including purity grade, host expression system, formulation buffer, molecular weight, and storage conditions.

Key quality attributes to verify upon receipt include:

• Purity: Assess by SDS-PAGE or HPLC; a purity of ≥90% is generally expected for recombinant proteins of this class, though exact values should be confirmed with the certificate of analysis (CoA).
• Biological Activity: Enzymatic activity can be assessed using standard glutamate dehydrogenase activity assays measuring NADH or NADPH production spectrophotometrically at 340 nm.
• Endotoxin Level: Critical for cell-based assays; confirm endotoxin content from the CoA prior to use in cell culture or in vivo experiments.
• Formulation and Stability: The protein is typically supplied in a stabilizing buffer; avoid repeated freeze-thaw cycles. Aliquot upon first use and store according to datasheet instructions, generally at −70 °C for long-term storage.

Research Applications

Recombinant Human GLUD2 Protein is a versatile research tool applicable across multiple experimental contexts:

• Enzyme Kinetics and Biochemistry: Characterize substrate specificity, cofactor preference (NAD⁺ vs. NADP⁺), and allosteric regulation by modulators such as ADP, GTP, and leucine. GLUD2 makes an excellent model for studying divergent regulatory evolution between GLUD1 and GLUD2.
• Drug Discovery and Inhibitor Screening: Use as a target protein in high-throughput screening assays for small-molecule modulators relevant to neurological disorders or metabolic diseases.
• Structural Biology: Suitable as an antigen for antibody generation or as a reference protein in structural studies, pull-down assays, and protein–protein interaction experiments.
• Neuroscience and Metabolic Research: Investigate the role of GLUD2 in glutamate clearance, neuronal energy metabolism, and excitotoxicity models.
• Biomarker Research: GLUD2 has been explored as a potential biomarker in neurological conditions; recombinant protein can serve as a standard or positive control in immunoassay development.

Handling, Storage, and Safety Guidelines

Proper handling and storage of Recombinant Human GLUD2 Protein are essential to preserve biological activity and ensure experimental reproducibility:

• Receipt and Inspection: Upon receipt, immediately verify the shipment contents against the packing list and inspect for damage. Record the lot number and CoA details.
• Reconstitution: If supplied lyophilized, reconstitute with the recommended volume of sterile water or buffer as specified on the datasheet. Allow the vial to equilibrate to room temperature before opening, and dissolve gently without vortexing to prevent protein denaturation.
• Aliquoting: Prepare single-use aliquots immediately after reconstitution to prevent activity loss from repeated freeze-thaw cycles. Label aliquots with protein identity, concentration, date, and lot number.
• Storage Temperature: Store long-term at −70 °C. Short-term storage at −20 °C may be acceptable; refer to the product datasheet for exact recommendations.
• Safety: Handle as a potential biological material following your institution's biosafety guidelines. Although recombinant proteins are generally of low hazard, use appropriate personal protective equipment (gloves, lab coat, eye protection) and follow standard good laboratory practice (GLP).
• Carrier Proteins: If working at very low concentrations, consider supplementing with a carrier protein (e.g., BSA) as specified in the datasheet to stabilize activity.

Experimental Protocol: Glutamate Dehydrogenase Activity Assay

The following is a general guideline for measuring GLUD2 enzymatic activity using a spectrophotometric assay. Always validate conditions empirically for your specific experimental setup and refer to the product datasheet for any supplier-specific recommendations.

Materials Required:

• Recombinant Human GLUD2 Protein (rp372297)
• L-Glutamate (substrate)
• NAD⁺ or NADP⁺ (cofactor)
• Assay buffer (e.g., 50 mM potassium phosphate buffer, pH 7.4)
• UV-transparent 96-well plate or cuvette
• Spectrophotometer capable of reading at 340 nm

General Procedure:

1. Prepare assay buffer and pre-warm to 37 °C.
2. Prepare a reaction mixture containing L-glutamate (e.g., 10 mM) and NAD⁺ (e.g., 1 mM) in assay buffer.
3. Add Recombinant Human GLUD2 Protein at an appropriate concentration (optimize empirically; typically in the nanogram-to-microgram range per reaction).
4. Initiate the reaction by adding the enzyme and immediately begin recording absorbance at 340 nm at regular intervals (e.g., every 30 seconds for 10 minutes).
5. Calculate enzyme activity from the linear phase of NADH or NADPH production using the molar extinction coefficient of NADH (ε = 6,220 M⁻¹ cm⁻¹ at 340 nm).
6. Include a no-enzyme blank control to account for background absorbance drift.

Note: Specific enzyme concentrations, substrate concentrations, buffer compositions, and incubation parameters should be optimized for each experimental context. The above values are starting points based on general GDH activity assay methodology.

Frequently asked questions

What is the difference between GLUD1 and GLUD2, and why does it matter for my research?

GLUD1 is ubiquitously expressed across human tissues, while GLUD2 is a primate-specific isoform predominantly expressed in the brain, testes, and retina. GLUD2 shows distinct allosteric regulation compared to GLUD1, including reduced sensitivity to GTP inhibition and enhanced activation by ADP. This makes GLUD2 particularly relevant for neuroscience research focused on neural energy metabolism, glutamate homeostasis, and brain-specific metabolic pathways.

How should I verify the activity of Recombinant Human GLUD2 Protein upon receipt?

Enzymatic activity of GLUD2 can be confirmed using a standard glutamate dehydrogenase activity assay: incubate the protein with L-glutamate and NAD⁺ (or NADP⁺) in an appropriate buffer at 37 °C, and monitor the production of NADH or NADPH spectrophotometrically at 340 nm. Compare results against the activity specification stated in the certificate of analysis (CoA) provided with the product. Running a no-enzyme blank control is essential to account for background signal.

What are the recommended storage conditions to maintain protein stability?

Recombinant Human GLUD2 Protein should be stored at −70 °C for long-term preservation of activity. Avoid repeated freeze-thaw cycles, which can denature the protein and reduce enzymatic activity. Upon first use, aliquot the protein into single-use volumes, label each aliquot clearly, and store them appropriately. Always consult the product-specific datasheet for exact storage buffer composition, recommended temperature, and shelf-life information.

Can Recombinant Human GLUD2 Protein be used in cell-based assays?

Yes, recombinant proteins can be used in cell-based assay contexts, for example as extracellular standards, in antibody validation, or in cell-free reconstitution systems. For direct intracellular applications, specialized delivery methods would be required. If using in cell culture, always verify endotoxin levels from the CoA, as high endotoxin contamination can confound cellular responses. Confirm suitability for your specific cell-based application with the product datasheet.

References

1. Plaitakis A, Zaganas I. Regulation of human glutamate dehydrogenases: implications for glutamate, ammonia and energy metabolism in brain. J Neurosci Res. 2001;66(5):899-908.
2. Spanaki C, Plaitakis A. The role of glutamate dehydrogenase in mammalian ammonia metabolism. Neurotox Res. 2012;21(1):117-127.
3. Aladdin Scientific. Recombinant Human GLUD2 Protein, SKU: rp372297. Product Datasheet.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.