Recombinant Human GLDC Protein: Research Guide & Protocol

Recombinant Human GLDC Protein is a research-grade recombinant form of the glycine decarboxylase enzyme, a key component of the mitochondrial glycine cleavage system, supplied by Aladdin Scientific to support studies in glycine metabolism, one-carbon metabolism, and related disease mechanisms.

Product Name

Recombinant Human GLDC Protein

SKU

rp371612

Gene / Target

GLDC (Glycine Decarboxylase)

Biological Function

P-protein subunit of the mitochondrial glycine cleavage system; catalyzes oxidative decarboxylation of glycine

Species

Human (Homo sapiens)

Application Areas

Glycine metabolism studies, one-carbon metabolism, NKH disease research, cancer metabolism, enzyme activity assays

Storage Recommendation

Avoid repeated freeze-thaw cycles; store at -20°C or -80°C as recommended; add carrier protein if required

Background: GLDC and the Glycine Cleavage System

Glycine decarboxylase (GLDC), also known as the P-protein of the glycine cleavage system (GCS), is a mitochondrial enzyme encoded by the GLDC gene. The GCS is a multi-enzyme complex comprising four proteins: the P-protein (GLDC), H-protein (GCSH), T-protein (GCST), and L-protein (dihydrolipoamide dehydrogenase, DLD). Together, these proteins catalyze the reversible oxidative decarboxylation of glycine, coupled to the reduction of NAD⁺ and transfer of a one-carbon unit to tetrahydrofolate (THF), generating 5,10-methylenetetrahydrofolate.

GLDC is the pyridoxal-5'-phosphate (PLP)-dependent component that initiates glycine cleavage. It is highly expressed in tissues with active one-carbon metabolism, including the liver, kidney, and brain. Loss-of-function mutations in GLDC are the predominant cause of non-ketotic hyperglycinemia (NKH), a severe inborn error of metabolism. More recently, GLDC has attracted attention in cancer biology, where glycine catabolism and one-carbon metabolism are reprogrammed to support rapid cell proliferation.

Recombinant Human GLDC Protein provides researchers with a well-defined, human-sequence enzyme for in vitro biochemical, structural, and functional studies.

Product Specifications and Quality Attributes

Aladdin Scientific's Recombinant Human GLDC Protein (SKU: rp371612) is produced using recombinant expression technology to yield a human-sequence GLDC suitable for research applications. The following general attributes apply to recombinant proteins of this class; researchers should consult the certificate of analysis (CoA) supplied with each lot for confirmed values:

• Source: Recombinant expression system (refer to product datasheet for host system details)
• Sequence: Human GLDC amino acid sequence (UniProt P23378)
• Tag: Refer to current product datasheet for tag configuration
• Purity: Verify lot-specific purity from the accompanying CoA; typical research-grade recombinant proteins are >85% by SDS-PAGE
• Formulation: Supplied in a stabilizing buffer; refer to datasheet for exact buffer composition
• Molecular Weight: The mature GLDC protein has a predicted molecular weight of approximately 114 kDa; observed MW may vary depending on expression system and any affinity tags

Note: Specific lot data including exact purity, endotoxin levels, and activity should be verified from the product CoA. Contact Aladdin Scientific technical support for the current datasheet.

Handling, Reconstitution, and Storage Protocol

Proper handling of recombinant proteins is essential to preserve biological activity and ensure reproducible experimental results. Follow the guidelines below when working with Recombinant Human GLDC Protein:

Upon Receipt

1. Briefly centrifuge the vial before opening to collect all material at the bottom.
2. Record the lot number and verify the CoA values against the product datasheet.
3. If the protein is supplied lyophilized, allow the vial to equilibrate to room temperature before reconstitution.

Reconstitution (Lyophilized Format)

1. Reconstitute with sterile, nuclease-free water or the buffer recommended on the datasheet.
2. Add the reconstitution volume gently along the wall of the vial; do not vortex.
3. Allow to dissolve for 10 minutes at room temperature, then gently pipette to mix.
4. If the protein is to be used in activity assays, reconstitute in an assay-compatible buffer (e.g., phosphate-buffered saline with 0.1% BSA as carrier).

Aliquoting

1. Prepare single-use aliquots immediately after reconstitution to minimize freeze-thaw cycles.
2. Aliquot volume should be appropriate to the planned experimental use to avoid wastage.

Storage Conditions

• Store working aliquots at -20°C for short-term use (up to 1 month).
• For long-term storage, keep at -80°C.
• Avoid repeated freeze-thaw cycles, which can cause protein aggregation and loss of activity.
• Adding a carrier protein such as 0.1% BSA is recommended if the protein will be stored at low concentrations.

Always refer to the specific storage instructions on the product label and CoA, as formulation may vary between lots.

Research Applications

Recombinant Human GLDC Protein is suited to a range of research applications in biochemistry, metabolic disease, and cancer biology:

• Enzyme Activity Assays: GLDC can be used as a positive control or substrate source in glycine cleavage system activity measurements, including radiolabeled glycine decarboxylation assays and coupled spectrophotometric assays monitoring NADH production.
• Protein Interaction Studies: GLDC interacts with the H-protein (GCSH) as part of the glycine cleavage multienzyme complex. Pull-down assays and surface plasmon resonance (SPR) studies using recombinant GLDC can map binding interfaces and assess the impact of disease-associated mutations.
• Structural Biology: Recombinant GLDC can be used in crystallography and cryo-electron microscopy studies aimed at resolving the human GCS structure and understanding catalytic mechanisms.
• Antibody Validation: As a defined antigen, Recombinant Human GLDC Protein serves as a positive control in Western blotting, ELISA, and immunoprecipitation experiments to validate anti-GLDC antibodies.
• Disease Modeling — NKH: Recombinant wild-type GLDC provides a biochemical reference for comparing the enzymatic activity of NKH-associated mutant variants expressed in vitro.
• Cancer Metabolism Research: GLDC overexpression has been reported in certain tumor types. Recombinant GLDC can support in vitro studies of its role in supporting serine/glycine biosynthesis and one-carbon flux in cancer cells.

Quality Control and Troubleshooting

To achieve reliable results with Recombinant Human GLDC Protein, researchers should consider the following quality-control practices and common troubleshooting steps:

Quality Control Checks

• Confirm protein identity by SDS-PAGE or Western blot using a validated anti-GLDC antibody before use in sensitive assays.
• Verify protein concentration by BCA or Bradford assay upon reconstitution; do not rely solely on the nominal concentration listed on the vial label.
• Check for aggregation by dynamic light scattering (DLS) if the protein will be used in binding or structural studies.

Common Issues and Solutions

Issue	Possible Cause	Solution
Low or absent enzyme activity	Protein degradation due to improper storage or freeze-thaw	Use freshly prepared aliquots; ensure cold chain was maintained during shipping
Unexpected band size on SDS-PAGE	Presence of affinity tag or incomplete processing of mitochondrial targeting sequence	Confirm expected MW from CoA; consult datasheet for tag information
High background in ELISA/WB	Aggregation or non-specific binding	Centrifuge at 10,000 × g for 5 min before use; optimize blocking conditions
Poor solubility after reconstitution	Reconstituted in incompatible buffer	Use buffer recommended on datasheet; avoid extreme pH

For product-specific technical assistance, contact Aladdin Scientific customer support with the lot number and CoA details.

Frequently asked questions

What is the biological function of GLDC?

GLDC encodes the P-protein of the mitochondrial glycine cleavage system (GCS), which catalyzes the pyridoxal phosphate-dependent oxidative decarboxylation of glycine. This reaction releases CO₂, transfers a one-carbon unit to tetrahydrofolate, and reduces NAD⁺ to NADH, linking glycine catabolism to one-carbon and folate metabolism.

What disease is associated with GLDC mutations?

Mutations in the GLDC gene are the most common cause of non-ketotic hyperglycinemia (NKH), an autosomal recessive inborn error of amino acid metabolism. NKH results from impaired glycine cleavage, leading to toxic accumulation of glycine in plasma, urine, and cerebrospinal fluid, causing severe neurological symptoms. Recombinant wild-type GLDC protein serves as a biochemical reference in studies of NKH-associated variants.

How should I avoid loss of activity when storing Recombinant Human GLDC Protein?

To preserve activity, aliquot the protein into single-use volumes immediately after reconstitution to avoid repeated freeze-thaw cycles. Store aliquots at -80°C for long-term preservation. If working at low protein concentrations, add a carrier protein such as 0.1% BSA to stabilize the protein. Always keep the protein on ice during experimental workflows.

Can Recombinant Human GLDC Protein be used as a positive control in Western blotting?

Yes. Because Recombinant Human GLDC Protein has a defined sequence and concentration, it is well suited as a positive control antigen in Western blot experiments to validate the specificity and sensitivity of anti-GLDC antibodies. Users should confirm the expected molecular weight from the current CoA, as the observed band position may vary depending on the expression system and any affinity tags present.

What expression system is used to produce Recombinant Human GLDC Protein?

The specific expression host system used for Recombinant Human GLDC Protein (rp371612) should be confirmed from the current Aladdin Scientific product datasheet or certificate of analysis, as expression platforms may vary. Researchers should consult the datasheet for information on the host organism, purification method, and any post-translational modifications relevant to their application.

References

1. Kikuchi G, Motokawa Y, Yoshida T, Hiraga K. Glycine cleavage system: reaction mechanism, physiological significance, and hyperglycinemia. Proc Jpn Acad Ser B Phys Biol Sci. 2008;84(7):246-263. doi:10.2183/pjab.84.246
2. Kure S, Kato K, Dinopoulos A, et al. Comprehensive mutation analysis of GLDC, AMT, and GCSH in nonketotic hyperglycinemia. Hum Mutat. 2006;27(4):343-352. doi:10.1002/humu.20308
3. Zhang WC, Shyh-Chang N, Yang H, et al. Glycine decarboxylase activity drives non-small cell lung cancer tumor-initiating cells and tumorigenesis. Cell. 2012;148(1-2):259-272. doi:10.1016/j.cell.2011.11.024
4. UniProt Consortium. UniProt entry P23378 (GCSP_HUMAN): Glycine dehydrogenase (decarboxylating), mitochondrial. UniProt Knowledgebase.

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