ogdh-2 Antibody

What is OGDH and why is it important in cellular metabolism?

OGDH (2-oxoglutarate dehydrogenase, mitochondrial) is a key enzyme in the Krebs (citric acid) cycle that catalyzes the conversion of 2-oxoglutarate (alpha-ketoglutarate) to succinyl-CoA and CO₂. It functions as the E1 component of the 2-oxoglutarate dehydrogenase complex (OGDHC), participating in the first, rate-limiting step of this conversion . OGDH catalyzes the irreversible decarboxylation of 2-oxoglutarate via thiamine diphosphate (ThDP) cofactor and transfers the decarboxylated acyl intermediate to an oxidized dihydrolipoyl group covalently amidated to the E2 enzyme (DLST) .

The OGDH complex is critical for the oxidation of fuel molecules including carbohydrates, fatty acids, and amino acids, making it central to cellular energy metabolism . Recent research has also identified that a fraction of the OGDH complex localizes to the nucleus where it associates with KAT2A on chromatin and provides succinyl-CoA for histone succinyltransferase activity, suggesting additional roles beyond metabolism .

What applications are OGDH antibodies commonly used for in research?

OGDH antibodies have been validated for numerous research applications:

These applications enable researchers to investigate OGDH expression, localization, protein interactions, and function in various experimental contexts, from basic metabolic studies to disease models .

What are the storage and handling recommendations for OGDH antibodies?

Optimal storage conditions for OGDH antibodies vary by formulation:

• Temperature: Most OGDH antibodies should be stored at -20°C , though some formulations require storage at 2-8°C

• Buffer composition: Commonly PBS with 0.02% sodium azide and 50% glycerol pH 7.3 or Hepes-Buffered Saline (HBS) with 0.02% sodium azide

• Stability: Typically stable for one year after shipment when stored properly

• Aliquoting: While some manufacturers indicate aliquoting is unnecessary for -20°C storage , others recommend creating aliquots to avoid repeated freeze/thaw cycles

For optimal performance, researchers should follow the specific storage guidelines provided by the manufacturer of their particular antibody.

How can I optimize Western blotting protocols for OGDH detection?

Optimizing Western blotting for OGDH detection requires careful consideration of several parameters:

Sample Preparation and Protein Loading:

• OGDH has an observed molecular weight of approximately 116 kDa

• Successful detection has been reported in various samples including heart tissue, liver tissue, lung tissue, and cell lines such as A549 and ROS1728

• RIPA lysis buffer has been effectively used for protein extraction

Antibody Selection and Dilution:

• Primary antibody dilutions range from 1:2500 to 1:10000 depending on the specific antibody

• For HRP-conjugated secondary antibodies, a dilution of 1:10,000 has been successfully employed

Detection and Quantification:

• Enhanced chemiluminescence substrates (e.g., Clarity ECL) provide effective visualization

• Imaging can be performed using systems such as Chemidoc MP

• Quantification of bands can be accomplished using software like ImageLab followed by statistical analysis with GraphPad Prism

When comparing OGDH expression between experimental conditions, statistical methods such as Kruskal-Wallis tests for multiple comparisons or Wilcoxon tests for pairwise comparisons have been employed in published research .

What methodological considerations are critical for immunohistochemistry with OGDH antibodies?

Successful immunohistochemistry (IHC) with OGDH antibodies involves several key methodological considerations:

Tissue Preparation and Antigen Retrieval:

• Heat-mediated antigen retrieval is recommended, with either:

  • TE buffer at pH 9.0 (preferred method)

  • Citrate buffer at pH 6.0 (alternative method)

• Paraffin-embedded tissues have been successfully used with OGDH antibodies

Antibody Dilution and Incubation:

• Recommended dilution ranges from 1:20 to 1:500

• A dilution of 1:200 has been successfully used for human lung cancer tissue

Detection Systems:

• Secondary antibody selection should match the host species of the primary antibody

• Visualization can be achieved using standard IHC detection systems compatible with the secondary antibody

Controls:

• Positive control tissues include human lung cancer tissue

• Negative controls should include omission of primary antibody and, ideally, tissues known to be negative for OGDH

For optimal results, researchers should perform antibody titration experiments to determine the ideal concentration for their specific tissue type and experimental system.

How can I distinguish between OGDH and its homolog OGDHL in my experiments?

Distinguishing between OGDH and its homolog OGDHL (which shares 79% sequence identity with OGDH) presents a significant challenge in research . Several methodological approaches can help ensure specificity:

Antibody Selection and Validation:

• Use antibodies targeting regions where OGDH and OGDHL sequences differ

• Verify antibody specificity through knockout/knockdown experiments

• Be aware that even with carefully selected antibodies, cross-reactivity may occur

Functional Assays:

• OGDH and OGDHL can be distinguished functionally, as studies have shown differential enzymatic activity

• Transient transfection experiments have demonstrated that OGDHL overexpression does not increase 2-oxo acid dehydrogenase activity with either OA or OG substrates

Genetic Approaches:

• CRISPR-Cas9 knockout systems provide definitive controls for antibody validation

• siRNA knockdown of OGDH or OGDHL can help confirm antibody specificity

Protein Identification:

• Mass spectrometry analysis of immunoprecipitated proteins can confirm identity

• Proteomic approaches can distinguish between OGDH and OGDHL based on unique peptides

What experimental approaches can be used to study OGDH interactions with other proteins in the OGDH complex?

Several complementary approaches have been successfully employed to study OGDH protein interactions:

Immunoprecipitation (IP) and Co-immunoprecipitation (Co-IP):

• IP experiments using OGDH antibodies have successfully pulled down components of the OGDH complex

• In mouse liver studies, IP with DHTKD1 antibodies co-precipitated OGDH, DLST, and DLD, suggesting formation of a hybrid complex

• IP of DLST from mouse liver revealed stable complexes between DLST, DLD, OGDH, and DHTKD1

Validation Through Knockout Systems:

• To confirm specificity, perform parallel IP experiments in control and knockout cell lines

• IP using anti-DHTKD1 antibody co-precipitated OGDH in control HEK-293 lysates but not in HEK-293 DHTKD1 KO lysates

Proteomic Analysis:

• Mass spectrometry analysis of gel slices from IP experiments can identify interacting proteins

• Proteomic approaches identified OGDH, DLST, and DLD as interacting partners of DHTKD1

Enzymatic Activity Assays:

• Enzymatic activity measurements can provide functional validation of protein interactions

• OGDHc activity in HEK-293 KO cell lysates showed 4-15% residual activity in triple KO lines and 18-46% in double KO lines

These approaches have revealed important insights, such as the finding that DHTKD1 and OGDH can form a hybrid complex containing components of both the OGDHc and OADHc .

How can I design experiments to study disease-associated OGDH variants using antibodies?

Research on disease-associated OGDH variants has employed several valuable experimental approaches:

Expression Analysis in Patient-Derived Cells:

• Fibroblast cells from affected individuals compared with control fibroblasts provide a physiologically relevant model

• Protein extraction using RIPA lysis buffer followed by immunoblotting with OGDH antibodies allows quantification of expression levels

Protein Stability Assessment:

• Cycloheximide chase experiments at varying concentrations (0-50 μg/mL) can assess protein stability

• After cycloheximide treatment (e.g., 24 hours), extract protein and measure OGDH levels by immunoblotting

• Normalize to appropriate loading controls (e.g., TOM20 for mitochondrial proteins)

Statistical Analysis:

• For comparing variant proteins to wild-type, Kruskal-Wallis tests or one-sample Wilcoxon tests are appropriate

• For analyzing treatment effects across genotypes, two-way analysis of variance can be employed

Recombinant Protein Analysis:

• Transfection of wild-type and mutant OGDH constructs (e.g., FLAG-tagged) in appropriate cell lines

• Immunoblotting with anti-FLAG or OGDH antibodies to compare expression levels

• Functional assays to assess enzymatic activity of variant proteins

These approaches have helped establish biallelic variants in OGDH as causes of neurodevelopmental disorders, providing insights into pathological mechanisms .

How can I validate the specificity of OGDH antibodies in my experimental system?

Validating OGDH antibody specificity is crucial for accurate data interpretation:

Understanding Isoform Recognition:

• OGDH has three isoforms produced by alternative splicing

• Some antibodies recognize specific isoforms; for example, antibody 15212-1-AP is immunized with the C-terminal region and recognizes isoforms 1 and 2

Knockout/Knockdown Controls:

• CRISPR-Cas9-mediated knockout cells provide the gold standard negative control

• siRNA knockdown can provide partial depletion for antibody validation

• Published studies have used OGDH KO cell lines to validate antibody specificity

Recombinant Protein Controls:

• Overexpression of tagged OGDH can serve as a positive control

• Competition experiments with recombinant protein can confirm specificity

Cross-Reactivity Assessment:

• Be aware of potential cross-reactivity with homologs like OGDHL (79% sequence identity)

• Consider testing in systems where OGDHL is absent or depleted

Multiple Antibody Comparison:

• Use multiple antibodies targeting different epitopes to confirm results

• Compare monoclonal and polyclonal antibodies for consistent detection

These validation steps are essential for ensuring reliable results, particularly when studying OGDH in complex biological systems.

What controls should be included when using OGDH antibodies in immunofluorescence experiments?

For reliable immunofluorescence experiments with OGDH antibodies, several controls are essential:

Cellular Controls:

• Positive control: Cells known to express OGDH (e.g., HepG2, A549, HeLa cells)

• Negative control: Cells with OGDH knockdown/knockout if available

• Primary antibody omission: To assess non-specific binding of secondary antibodies

Co-staining Controls:

• Mitochondrial markers: Since OGDH primarily localizes to mitochondria, co-staining with mitochondrial markers (e.g., TOM20, MitoTracker) confirms proper localization

• Nuclear counterstain: DAPI staining helps visualize nuclei and cell boundaries

• Cytoskeletal markers: Phalloidin has been used to visualize cell structure alongside OGDH staining

Technical Parameters:

• Recommended dilutions range from 1:50 to 1:500 for IF/ICC applications

• Successful staining has been demonstrated with ethanol fixation (-20°C) for certain cell types

• Secondary antibody selection should match the host species (typically anti-rabbit or anti-mouse depending on the primary antibody)

Published studies have shown OGDH localization primarily in mitochondria, with some nuclear localization also reported , making proper controls essential for distinguishing genuine localization patterns from artifacts.

How should I interpret OGDH antibody data in functional studies of the TCA cycle?

Interpreting OGDH antibody data in functional TCA cycle studies requires careful consideration:

Expression vs. Activity:

• OGDH protein levels (detected by antibodies) may not directly correlate with enzymatic activity

• Consider complementing antibody-based detection with functional assays measuring OGDH complex activity

Complex Formation Analysis:

• OGDH functions as part of a multi-protein complex with DLST and DLD

• Co-immunoprecipitation studies can assess whether detected OGDH is incorporated into functional complexes

• The integrity of the complex, not just OGDH levels, determines TCA cycle function

Substrate Specificity Considerations:

• OGDH primarily catalyzes the decarboxylation of 2-oxoglutarate but can also act on 2-oxoadipate at a lower rate

• When interpreting metabolic studies, consider this substrate overlap and potential functional redundancy with DHTKD1

Compensatory Mechanisms:

• Studies in knockout models have revealed compensatory relationships between OGDH and DHTKD1

• In DHTKD1 knockout systems, OGDH can partially compensate for lost function

• Triple knockout studies (GCDH/DHTKD1/OGDH) showed unique metabolic profiles compared to double knockouts

A comprehensive analysis should integrate protein expression data from antibody-based methods with functional assays and metabolite measurements to fully understand OGDH's role in TCA cycle function.

How can OGDH antibodies be used to study mitochondrial dysfunction in disease?

OGDH antibodies provide valuable tools for investigating mitochondrial dysfunction in various disease contexts:

Neurodevelopmental Disorders:

• OGDH antibodies have been used to characterize biallelic variants in OGDH causing global developmental delay

• Patient-derived fibroblasts can be analyzed for OGDH protein levels and compared to controls

• Cycloheximide chase experiments can assess protein stability differences between wild-type and mutant OGDH

Metabolic Disorders:

• OGDH and DHTKD1 have been studied in glutaric aciduria type 1, revealing complex metabolic interactions

• Antibody-based studies in knockout models have shown how OGDH contributes to disease-relevant metabolite accumulation

Methodological Approach:

• Establish appropriate cellular models (patient-derived cells or engineered cell lines)

• Use OGDH antibodies to assess protein expression by Western blotting

• Perform subcellular localization studies using immunofluorescence

• Analyze OGDH complex formation through co-immunoprecipitation

• Correlate antibody-based findings with functional and metabolic measurements

This integrated approach has revealed, for example, that certain OGDH variants lead to reduced protein levels, potentially explaining the pathophysiology of associated neurodevelopmental disorders .

What insights have OGDH antibody studies provided about enzyme complex formation?

Research using OGDH antibodies has revealed important insights into the formation and regulation of oxoacid dehydrogenase complexes:

Hybrid Complex Formation:

• Immunoprecipitation studies using DHTKD1 antibodies revealed that OGDH can form a hybrid complex with DHTKD1, DLST, and DLD

• This finding was confirmed through reciprocal co-IP experiments and validated in knockout cell lines

Complex Component Analysis:

• IP of DLST from mouse liver confirmed the formation of stable complexes between DLST, DLD, OGDH, and DHTKD1

• Mass spectrometry analysis of immunoprecipitated complexes identified specific interacting partners

Functional Redundancy:

• Enzymatic activity measurements in knockout cells revealed that OGDH contributes to the oxidative decarboxylation of 2-oxoadipate, traditionally considered a DHTKD1 substrate

• DHTKD1 may also contribute to the oxidation of 2-oxoglutarate, as evidenced by lower OGDHc activities in triple KO cell lines

Complex Localization:

• Most OGDH functions as part of mitochondrial complexes, but a fraction localizes to the nucleus where it interacts with KAT2A and participates in histone modification

These findings demonstrate how antibody-based approaches have transformed our understanding of OGDH biology, revealing unexpected protein interactions and functional redundancies that may have important implications for metabolic regulation and disease mechanisms.

How can OGDH antibodies contribute to research on metabolic regulation of gene expression?

Recent research has revealed unexpected roles for OGDH beyond core metabolism, particularly in regulating gene expression:

Nuclear Localization and Function:

• A fraction of the OGDH complex localizes to the nucleus where it associates with chromatin

• OGDH antibodies can be used in subcellular fractionation and immunofluorescence studies to confirm nuclear localization

Histone Modification Mechanisms:

• Nuclear OGDH provides succinyl-CoA to histone succinyltransferase KAT2A

• Co-immunoprecipitation with OGDH antibodies can help identify nuclear interaction partners

Experimental Approaches:

• Chromatin immunoprecipitation (ChIP) with OGDH antibodies to identify genomic binding sites

• Co-IP experiments to identify nuclear protein interaction networks

• Immunofluorescence co-localization with nuclear markers and chromatin-associated proteins

• Cell fractionation followed by Western blotting to quantify nuclear vs. mitochondrial OGDH

These approaches can provide insights into how metabolic enzymes like OGDH directly participate in epigenetic regulation, potentially linking cellular metabolic state to gene expression patterns—a rapidly expanding field of research.

What are the key considerations when using OGDH antibodies in ELISA-based applications?

OGDH ELISA applications require specific methodological considerations:

Antibody Selection:

• Commercial OGDH ELISA kits typically use a double antibody-sandwich ELISA method

• The microplate is precoated with anti-OGDH antibody, and detection uses biotinylated detection antibody

Sample Preparation:

• Compatible sample types include serum, plasma, cell culture supernatant, cell or tissue lysate

• Appropriate dilution of samples is critical for staying within the detection range

Assay Performance:

• Typical detection range: 0.156-10ng/ml

• Sensitivity: approximately 0.094ng/ml

• Assay duration: typically 4 hours

Procedure Overview:

• Add standard and properly diluted samples to antibody-coated wells

• Incubate and wash to remove unbound components

• Add biotinylated detection antibody

• Wash and add HRP-Streptavidin Conjugate (SABC)

• Add TMB substrate solution, which produces a blue color product that turns yellow after adding stop solution

• Read optical density at 450nm

• Calculate OGDH concentration using standard curve

For optimal results, researchers should validate the assay for their specific sample type and carefully follow the manufacturer's protocol for timing, washing steps, and reagent preparation.