Types, Selection Principles, and Experimental Applications of Loading Control Antibodies

Loading control antibodies are used to detect stable reference proteins and provide internal references for target protein quantification, sample-to-sample comparison, evaluation of subcellular fractions, and multiplex detection. Their applicability depends on reference protein stability, sample type, subcellular localization, the mechanism of experimental intervention, and the detection system.

Keywords: loading control antibodies; Loading Control; reference proteins; protein normalization; subcellular fractionation; multiplex detection

1 Functions and Experimental Positioning of Loading Control Antibodies

1.1 Loading Control Antibodies and Reference Proteins

Loading control antibodies are used to recognize reference proteins in experimental systems, while the normalization or internal reference function is actually performed by the detected reference protein itself. GAPDH, β-Actin, and Tubulin are mainly used as whole-cell or cytoplasmic reference proteins, whereas Histone H3, Lamin, COX IV, Hsp60, and ATP1A1 are respectively suitable for specific subcellular fractions such as the nucleus, mitochondria, or plasma membrane. Only when a reference protein remains relatively stable in the defined sample and experimental conditions can its antibody signal serve as an effective internal reference.

1.2 Major Functions of Loading Control Antibodies

(1) Relative Quantification of Target Proteins

In Western blot and other quantitative immunoassays, stable reference proteins can be used to correct technical differences arising from sample loading, protein extraction efficiency, and the detection workflow, thereby improving comparability of target protein quantification among different samples.

(2) Evaluation of Subcellular Fractions

Nuclear-cytoplasmic fractionation, mitochondrial extraction, and membrane-protein enrichment experiments require reference proteins with defined localization to evaluate enrichment of the target fraction, fraction content among different samples, and possible cross-contamination.

(3) Reference for Imaging and Multichannel Detection

In immunofluorescence, immunocytochemistry, and applicable multiparameter detection systems, stable reference proteins can be used to establish an internal reference channel to assist comparison of target signals among different cells, different subcellular regions, or different treatment conditions.

(4) Experimental Quality Control

Abnormal changes in reference proteins may result either from direct effects of the experimental treatment on their expression or localization or from deviations in sample amount, fractionation efficiency, or detection conditions. Therefore, loading control signals can serve as important indicators for experimental quality assessment.

1.3 Loading Control Antibodies and Other Experimental Controls

Loading control antibodies, positive controls, negative controls, isotype controls, and fractionation markers perform different experimental functions. Loading controls are mainly used to establish an internal comparison baseline; positive controls are used to verify the ability of the detection system to recognize the target protein; negative or isotype controls are used to evaluate nonspecific background; fractionation markers are used to assess the purity of subcellular fractions. Some proteins can serve as both loading controls and fractionation markers, but their evaluation level should be defined according to the specific experimental purpose.

Table 1 Functional Positioning of Different Experimental Controls

Type	Major Function	Typical Application	Common Examples
Loading control protein	Establish an internal comparison baseline	Relative quantification and sample normalization	GAPDH, β-Actin, Tubulin
Subcellular reference	Evaluate specific fractions	Nuclear, mitochondrial, and membrane-protein analysis	Histone H3, COX IV, ATP1A1
Positive control	Verify detection validity	Confirmation of antibody specificity and detection performance	Samples known to express the target protein
Negative/isotype control	Evaluate nonspecific background	Immunoassays such as IF and FC	Isotype IgG, unstained samples
Total protein/sample amount reference	Independent normalization	Protein quantification and complex-sample comparison	Total protein staining, cell number

1.4 Basic Conditions for Valid Loading Controls

(1) Reference Protein Stability

Candidate reference proteins should not show systematic changes related to the experimental treatment among control groups, treatment groups, or key dose and time conditions.

(2) Relative Independence From the Research Mechanism

The reference protein should not directly participate in the core biological process affected by the experimental intervention. GAPDH should be used cautiously in glycolysis studies; Actin, Vinculin, Cofilin, and Profilin should be used cautiously in cytoskeletal and mechanotransduction studies; and Tubulin stability should be reassessed in microtubule intervention experiments.

(3) Matching Subcellular Localization

Whole-cell, cytoplasmic, nuclear, mitochondrial, and plasma-membrane samples have different protein compositions. Reference proteins should be selected according to the localization of the fraction being analyzed.

(4) Reliable Detection Signal

The antibody should have good specificity and reproducibility, and the detection signal should remain within an effective dynamic range. Fluorescence detection additionally requires control of background signal, channel crosstalk, photobleaching, and signal saturation.

2 Common Loading Control Proteins and Their Applicable Ranges

2.1 Whole-Cell and Cytoplasmic Loading Controls

(1) GAPDH

GAPDH has a typical molecular weight of approximately 36 kDa and is a common whole-cell and cytoplasmic reference protein. Hypoxia, glucose restriction, enhanced glycolysis, and metabolic reprogramming may alter its expression, so its stability should be validated before formal quantification in metabolism-related studies.

(2) β-Actin

β-Actin has a typical molecular weight of approximately 42 kDa and is an important component of the Actin cytoskeleton. EMT, cell migration, adhesion, mechanotransduction, and Actin remodeling may all affect its expression or state, so β-Actin should not be preset as a constant loading control in related studies.

(3) α-Tubulin and β-Tubulin

α-Tubulin and β-Tubulin form microtubule heterodimers and have typical molecular weights of approximately 50–55 kDa. They can be used in some whole-cell and cytoplasmic samples. Microtubule stabilizers, microtubule depolymerizing agents, mitotic arrest, and cell-cycle synchronization may all alter the state of the microtubule system, so their value as references should be reassessed in related studies.

(4) Vinculin

Vinculin has a typical molecular weight of approximately 116 kDa and can serve as a high-molecular-weight candidate reference protein. It participates in focal adhesion formation, FAK signaling, and mechanotransduction, so it should be used cautiously in adhesion- and cell-mechanics-related studies.

2.2 Cyclophilin, Cofilin, and Profilin

(1) Cyclophilin A/B

Cyclophilin A is mainly distributed in the cytoplasm, whereas Cyclophilin B is closely associated with the endoplasmic reticulum and secretory pathway. They can serve as candidate reference proteins other than GAPDH, Actin, and Tubulin. Their stability should be revalidated in studies of inflammation, oxidative stress, endoplasmic reticulum stress, and Cyclophilin-related mechanisms.

(2) Cofilin and Profilin

Cofilin and Profilin both participate in regulation of Actin dynamics and can serve as candidate reference proteins in experimental systems that do not directly interfere with the cytoskeleton. In studies of cell migration, invasion, adhesion, and cytoskeletal remodeling, their own changes have clear biological significance and therefore they should not be used as fixed loading controls.

2.3 Nuclear Protein Loading Controls

(1) Histone H3

Histone H3 is a core histone of the nucleosome and can be used for nuclear protein and chromatin-related samples. Total Histone H3 and modification-specific signals such as H3K9me2 should be strictly distinguished. Modification-specific antibodies reflect specific epigenetic modification states and cannot replace total Histone H3 as a nuclear protein reference.

(2) Lamin A/C and Lamin B1

Lamin A/C and Lamin B1 are structural proteins of the nuclear lamina and can be used in nuclear protein and nuclear-envelope-related experiments. Lamin B1 may decrease during cellular senescence, while Lamin A/C may also be affected by cell differentiation, nuclear mechanics, and nuclear-lamina remodeling.

(3) TBP and HDAC1

TBP is a component of the basal transcription machinery, while HDAC1 participates in chromatin deacetylation. They can serve as candidate reference proteins in some nuclear protein experiments. Their relevance to the experimental mechanism should be carefully evaluated in transcriptional regulation, HDAC inhibition, and epigenetic studies.

(4) YY1

YY1 is a nuclear transcriptional regulatory protein and can be used for specific nuclear protein detection or as a conditional reference. Because YY1 broadly participates in transcriptional regulation, its stability is highly dependent on experimental conditions and it should not be used as a universal nuclear loading control.

2.4 Mitochondrial Loading Controls

(1) COX IV

COX IV is located in the inner mitochondrial membrane and is a commonly used mitochondrial reference protein. Mitophagy, mitochondrial biogenesis, and respiratory-chain remodeling may alter its level, in which case COX IV may simultaneously reflect changes in mitochondrial mass and should not be used as a constant reference.

(2) Hsp60

Hsp60 is mainly located in the mitochondrial matrix and can be used for mitochondrial fractions and related protein studies. Mitochondrial stress and changes in protein homeostasis may affect its expression, so its stability should be validated in the specific experimental model.

(3) Grp75

Grp75 is a mitochondrial chaperone and can serve with COX IV and Hsp60 as mitochondrial reference candidates with different functional backgrounds. Its expression stability should be evaluated in studies of mitochondrial stress, protein folding, and mitochondrial dysfunction.

2.5 Plasma Membrane and Membrane-Structure Loading Controls

(1) ATP1A1

ATP1A1 encodes the Na⁺/K⁺-ATPase α1 subunit and is mainly located in the plasma membrane. It can be used for membrane-protein extraction and evaluation of membrane fractions. Studies of receptor internalization, membrane trafficking, and ion homeostasis may directly affect its expression or localization.

(2) Caveolin-1

Caveolin-1 is an important structural protein of Caveolae and can serve as a candidate reference in some membrane-protein and membrane-structure studies. Its stability should be reassessed in research involving Caveolae remodeling, membrane mechanical stress, and lipid metabolism.

2.6 Other Conditional Reference Proteins

Hsp70 can serve as a candidate reference protein in some experiments, but heat shock, oxidative stress, and proteotoxic stress can markedly induce its expression. Albumin and Transferrin show clear dependence on tissue, cell type, and secretion background and are more suitable for specific tissue, body-fluid, or transport-related studies. The reference value of these proteins depends more strongly on the specific sample and experimental conditions than that of traditional whole-cell loading controls.

Table 2 Experimental Positioning of Common Reference Proteins

Reference Protein	Major Localization	Major Application	Research Conditions Requiring Caution
GAPDH	Cytoplasm	Whole-cell and cytoplasmic loading control	Hypoxia, glycolysis, metabolic reprogramming
β-Actin	Cytoskeleton	Whole-cell loading control	EMT, migration, mechanotransduction
α/β-Tubulin	Microtubules	Whole-cell and cytoplasmic loading control	Microtubule drugs, cell cycle
Vinculin	Focal adhesions/cytoskeleton	High-molecular-weight candidate loading control	Adhesion, FAK, mechanical signaling
Cyclophilin A/B	Cytoplasm/endoplasmic-reticulum-related	Conditional reference	Inflammation, ER stress
Cofilin/Profilin	Actin regulation	Conditional reference	Migration, cytoskeletal remodeling
Histone H3	Chromatin	Nuclear protein loading control	Histone and chromatin research
Lamin A/C, B1	Nuclear lamina	Nuclear protein reference	Senescence, nuclear mechanics, differentiation
TBP, HDAC1	Nucleus	Nuclear protein reference	Transcription and epigenetic research
COX IV	Inner mitochondrial membrane	Mitochondrial reference	Mitophagy
Hsp60, Grp75	Mitochondria	Mitochondrial reference	Mitochondrial stress
ATP1A1	Plasma membrane	Membrane-protein reference	Membrane trafficking, ion homeostasis
Caveolin-1	Caveolae	Membrane-structure reference	Membrane remodeling
Hsp70	Cytoplasm, etc.	Conditional reference	Heat shock, stress

3 Major Experimental Applications of Loading Control Antibodies

3.1 Western Blot and Protein Quantification

Western blot usually normalizes the target protein signal to the signal of a stable reference protein to reduce technical deviations arising from protein quantification, loading, transfer, and imaging. In addition to reference protein stability, molecular-weight overlap and signal linearity should also be considered. For target proteins at approximately 35–40 kDa, interference from GAPDH should be considered; for target proteins at approximately 40–45 kDa, β-Actin should be considered; and for the approximately 50–55 kDa region, Tubulin band overlap should be considered. Highly abundant loading controls should also be prevented from reaching signal saturation.

3.2 Capillary Immunodetection and Automated Protein Analysis

Automated immunoassays such as capillary Western also require establishment of reference protein or total protein normalization systems. The biological stability principles for candidate reference proteins are the same as those for traditional Western blot, but antibody working range, sample loading amount, and detection linearity need to be independently validated according to the specific platform.

3.3 Subcellular Fractionation

(1) Nuclear-Cytoplasmic Fractionation

Histone H3, Lamin A/C, Lamin B1, or TBP can be selected for nuclear fractions, while GAPDH, Tubulin, or Cyclophilin A can be selected for cytoplasmic fractions. Reference proteins can be used for relative quantification and can also assist in evaluating the purity of nuclear-cytoplasmic separation.

(2) Mitochondrial Fractionation

COX IV, Hsp60, and Grp75 can be used to evaluate mitochondrial fractions. In Mitophagy or mitochondrial biogenesis experiments, these proteins may change together with total mitochondrial mass, so mitochondrial fraction references should be distinguished from mitochondrial-mass indicators.

(3) Membrane Protein Fractionation

ATP1A1 and Caveolin-1 can be used for plasma-membrane-related samples. If the experiment directly involves receptor internalization, Caveolae remodeling, or membrane trafficking, other membrane references or independent normalization methods should be used.

3.4 Immunofluorescence and Immunocytochemistry

Internal references in immunofluorescence and immunocytochemistry are mainly used to assist comparison of target signals according to cell number, cellular structure, subcellular region, or treatment condition, and their quantitative logic differs from that of Western blot. Stable reference proteins can serve as independent detection channels, but fixation, permeabilization, imaging parameters, and ROI selection should be kept consistent, and it should be confirmed that the reference protein itself is not markedly affected by the experimental treatment.

3.5 Multichannel Fluorescence Imaging

Directly labeled antibodies including AF405, AF488, AF555, AF594, AF647, AF700, AF750, FITC, TRITC, and Cy-series labels can be used for multichannel detection. When reference antibodies and target antibodies are detected simultaneously, channel combinations should be designed according to excitation/emission spectra, target protein abundance, reference signal intensity, and the detection platform, while controlling spectral crosstalk, signal saturation, and photobleaching.

3.6 Flow Cytometry and Multiparameter Detection

Flow cytometry and other multiparameter detection methods have independent normalization and quality-control systems. Traditional housekeeping protein normalization principles cannot directly replace positive, negative, FMO, or isotype controls. A reference protein can serve as an auxiliary internal reference only when it is stably expressed in the target cell population, relatively independent of the experimental mechanism, and the corresponding antibody has been validated for the intended application.

3.7 Immunohistological Detection

Tissue samples show marked heterogeneity in cellular composition and spatial distribution, and GAPDH, Actin, or Tubulin may not remain constant across different tissue regions. For relative signal comparison, internal references should be determined according to tissue type, target cell population, pathological state, and the spatial expression characteristics of the reference protein to avoid interference from changes in cellular composition.

3.8 Multiplex Immunodetection

HRP-, Biotin-, and directly fluorescent-conjugated antibodies can reduce the risk of secondary-antibody cross-reactivity and support multi-target detection within the same sample. Different labeling formats mainly affect the detection workflow and channel compatibility, while whether a reference protein can function as a loading control still depends on its biological stability.

3.9 Control Boundaries in Other Immunoassays

Co-IP, ChIP, ELISA, and protein arrays each have their own normalization and quality-control systems, and traditional Loading Controls are not universal references for all experimental steps. Co-IP is usually evaluated using Input, IgG, and IP products; ChIP is commonly normalized to Input, while IgG is used as a nonspecific-background or negative control; ELISA mainly depends on standard curves and quality-control samples. Loading control antibodies serve as internal references only when the experimental design explicitly requires a stable reference protein.

4 Selection Principles for Loading Control Antibodies

4.1 Screening According to Sample Type

For whole-cell and cytoplasmic samples, GAPDH, β-Actin, Tubulin, Vinculin, and Cyclophilin can be preferentially considered. For nuclear samples, Histone H3, Lamin, TBP, and HDAC1 can be screened. For mitochondrial samples, COX IV, Hsp60, and Grp75 can be considered. For membrane-protein samples, ATP1A1 and Caveolin-1 can be considered. Sample localization is the fundamental condition for selecting candidate loading controls.

4.2 Exclusion According to Experimental Mechanism

Table 3 Principles for Excluding Candidate Loading Controls Under Different Research Conditions

Experimental Condition	Reference Proteins Requiring Caution	Major Reason
Hypoxia, glycolysis	GAPDH	Glycolytic program changes
EMT, migration	β-Actin, Vinculin, Cofilin, Profilin	Cytoskeletal and adhesion remodeling
Microtubule drugs	α/β-Tubulin, βIII Tubulin	Microtubule system is directly affected
Cellular senescence	Lamin B1	May decrease during senescence
Epigenetic intervention	HDAC1, specific Histone modifications	Direct involvement in the research mechanism
Mitophagy	COX IV, Hsp60, Grp75	Mitochondrial mass changes
Heat shock	Hsp70	Stress-induced expression
Caveolae research	Caveolin-1	Membrane structure changes directly
ER stress	Cyclophilin B	Endoplasmic reticulum state changes
Cell-cycle research	PCNA, Cdk4	Cell-cycle dependent
Neural differentiation	βIII Tubulin	Differentiation marker
Smooth muscle/myofibroblast differentiation	ACTA2	Phenotypic marker

4.3 Selecting Antibodies According to Detection Method

Unconjugated antibodies can be flexibly combined with different secondary-antibody systems; HRP-conjugated antibodies can reduce secondary-antibody steps; Biotin labeling can be combined with Streptavidin systems; directly fluorescent-labeled antibodies are suitable for multichannel detection. Whether a specific product is suitable for WB, IF, ICC, FC, or other detection methods should be determined according to the actual application validation of the product.

4.4 Stability Validation

Before formal experiments, 2–3 candidate reference proteins with different functional backgrounds should preferably be selected and prescreened in control groups, major treatment groups, and key dose or time points. If a reference protein changes systematically with experimental treatment, it should be excluded from the loading control system. Complex experiments can additionally use total protein, cell number, or other independent normalization methods for cross-validation.

5 Conditional References and Phenotype-Related Proteins

5.1 PCNA and Cdk4

PCNA participates in DNA replication, while Cdk4 participates in cell-cycle regulation. Both can be used for proliferation- and cell-cycle-related detection, but in experiments involving cell-cycle synchronization, proliferation, senescence, or antitumor treatment, they themselves represent important experimental readouts and are therefore unsuitable as constant loading controls in the corresponding models.

5.2 βIII Tubulin

βIII Tubulin shows clear dependence on cell type and differentiation status and is a commonly used marker protein in neuronal cells and neural differentiation research. In studies of neural differentiation, neural injury, and neuronal phenotypes, it should be treated as an experimental indicator rather than a universal reference protein.

5.3 ACTA2 and Actin Isoforms

ACTA2 is closely associated with smooth muscle and myofibroblast phenotypes, and Actin isoforms such as ACTC1 and ACTG2 also show tissue- and cell-type dependence. Related antibodies are suitable for phenotype and Actin-family detection but should not be used as fixed loading controls in fibrosis, smooth muscle differentiation, or myofibroblast formation experiments.

5.4 γ-Tubulin and Centrin 2

γ-Tubulin and Centrin 2 are closely associated with centrosomes and microtubule-organizing centers and are mainly used for centrosome, microtubule nucleation, and mitosis-related detection. Their major value lies in structural and localization evaluation rather than routine whole-cell normalization.

5.5 Albumin and Transferrin

Albumin and Transferrin show clear dependence on tissue, cell type, and secretion background. Their antibodies are suitable for specific tissue, body-fluid, secretion, and transport-related experiments and are not suitable as universal loading controls across different cells and tissues.

6 Labeling Formats of Loading Control Antibodies

6.1 Unconjugated Antibodies

Unconjugated antibodies can be flexibly combined according to the primary antibody host and secondary-antibody system and are suitable for Western blot, immunofluorescence, immunocytochemistry, and other validated immunoassays. In multiplex experiments, cross-reactivity between different primary antibody hosts and secondary antibodies should be avoided.

6.2 HRP-Conjugated Antibodies

Direct HRP conjugation can reduce secondary-antibody incubation steps and is suitable for corresponding chemiluminescent or chromogenic systems. β-Actin, GAPDH, Cofilin, Hsp60, Vinculin, COX IV, Profilin 1, and β-Tubulin all have corresponding directly labeled products.

6.3 Biotin-Conjugated Antibodies

Biotin-conjugated antibodies can be detected using Streptavidin systems and are suitable for signal amplification or specific multiplex detection strategies. GAPDH, β-Actin, Cyclophilin B, Lamin A/C, Hsp60, Cofilin, Profilin 1, Caveolin-1, and Tubulin can all form different detection combinations.

6.4 Fluorescent-Conjugated Antibodies

Directly labeled antibodies using AF405, AF488, AF555, AF594, AF647, AF700, AF750, FITC, TRITC, and Cy-series fluorophores can be adapted to different fluorescence channels. The labeling format should be selected according to the detection platform, spectral compatibility, and target protein abundance. Direct fluorescent labeling itself cannot be used as the criterion for determining whether a reference protein is suitable as a loading control.

7 Loading Control Abnormalities and Result Interpretation

7.1 Changes in Reference Proteins Between Groups

When a single reference protein changes systematically with experimental treatment while other independent references or total protein remain stable, the protein should be considered regulated by the treatment and should no longer be used for normalization. When multiple reference proteins change simultaneously, broad biological changes should be distinguished from technical deviations caused by sample amount, protein extraction, or the detection workflow.

7.2 Abnormalities in Subcellular References

Abnormal nuclear, mitochondrial, or membrane reference signals may result from fractionation contamination or differences in fraction recovery and may also reflect experimental changes in the corresponding organelle or structure. Subcellular localization experiments should be interpreted comprehensively using multiple localization references together with changes in the target protein.

7.3 Abnormalities in Fluorescence References

Photobleaching, exposure saturation, elevated background, channel crosstalk, and differences in labeling efficiency can all affect fluorescence reference signals. Before quantification, both the reference and target channels should be confirmed to remain within stable and comparable detection ranges.

7.4 Inconsistent Results Between Different Loading Controls

When different candidate reference proteins produce inconsistent normalization results, their stability, detection linearity, and relevance to the experimental mechanism should be reassessed. If necessary, a third reference protein or an independent normalization method should be added for validation.

8 Loading Control Antibodies and Related Reference Products

Table 4 Selected Loading Control and Related Reference Antibodies

Cat. No.	Description	Grade & Purity	Reference Protein	Application Positioning
Ab090999	Recombinant beta Actin Antibody	Recombinant, ExactAb™, Validated, High Performance, See COA	β-Actin	Whole-cell/cytoplasmic loading control
Ab104788	Recombinant GAPDH Antibody	Recombinant, ExactAb™, Validated, High Performance, 0.5 mg/mL	GAPDH	Whole-cell/cytoplasmic loading control
Ab104781	Recombinant GAPDH Antibody	Recombinant, ExactAb™, Validated, High Performance, See COA	GAPDH	Whole-cell/cytoplasmic loading control
Ab091197	Recombinant beta Tubulin Antibody	Recombinant, ExactAb™, Validated, 0.2 mg/mL	β-Tubulin	Whole-cell/cytoplasmic loading control
Ab091196	Recombinant beta Tubulin Antibody	Recombinant, ExactAb™, Validated, High Performance, See COA	β-Tubulin	Whole-cell/cytoplasmic loading control
Ab088473	Recombinant Alpha Tubulin Antibody	Recombinant, ExactAb™, Validated, 0.25 mg/mL	α-Tubulin	Whole-cell/cytoplasmic loading control
Ab088465	Recombinant alpha Tubulin Antibody	Recombinant, ExactAb™, Validated, High Performance, See COA	α-Tubulin	Whole-cell/cytoplasmic loading control
Ab134233	Recombinant Vinculin Antibody	Recombinant, ExactAb™, Validated, High Performance, See COA	Vinculin	High-molecular-weight candidate loading control for whole-cell samples
Ab337908	Recombinant Histone H3 Antibody	Recombinant, ExactAb™, Validated, PBS Only, See COA	Histone H3	Nuclear protein loading control
Ab107980	Recombinant Histone H3 Antibody	Recombinant, ExactAb™, Validated, High Performance, 1.0 mg/mL	Histone H3	Nuclear protein loading control
Ab112659	Recombinant Lamin B1 Antibody	Recombinant, ExactAb™, Validated, High Performance, 0.3 mg/mL	Lamin B1	Nuclear protein loading control
Ab112660	Recombinant Lamin B1 Antibody	Recombinant, ExactAb™, Validated, High Performance, See COA	Lamin B1	Nuclear protein loading control
Ab112658	Lamin B1 Mouse mAb	Carrier Free, ExactAb™, Azide Free, Validated, High Performance, See COA	Lamin B1	Nuclear protein loading control
Ab130263	Recombinant TBP Antibody	Recombinant, ExactAb™, Validated, See COA	TBP	Nuclear protein reference
Ab130268	TBP Mouse mAb	Carrier Free, ExactAb™, Azide Free, Validated, See COA	TBP	Nuclear protein reference
Ab107012	Anti-HDAC1 antibody	Recombinant, ExactAb™, Validated, High Performance, 0.125 mg/mL	HDAC1	Nuclear protein reference
Ab107009	HDAC1 Mouse mAb	Carrier Free, ExactAb™, Azide Free, Validated, High Performance, See COA	HDAC1	Nuclear protein reference
Ab135077	Recombinant YY1 Antibody	Recombinant, ExactAb™, Validated, See COA	YY1	Nuclear transcription-related detection
Ab097410	Recombinant COX IV Antibody	Recombinant, ExactAb™, Validated, High Performance, 0.5 mg/mL	COX IV	Mitochondrial reference
Ab097409	Recombinant COX IV Antibody	Recombinant, ExactAb™, KD Validation, Validated, See COA	COX IV	Mitochondrial reference
Ab097414	COX IV Mouse mAb	ExactAb™, Validated, 2.0 mg/mL	COX IV	Mitochondrial reference
Ab097457	COX4I2 Antibody	Carrier Free, ExactAb™, Validated, 1.0 mg/mL	COX4I2	Mitochondrial respiratory-chain-related detection
Ab128631	Recombinant ATP1A1 Antibody	Recombinant, ExactAb™, Validated, High Performance, 0.5 mg/mL	ATP1A1	Plasma membrane reference
Ab128630	Recombinant Sodium Potassium ATPase/ATP1A1 Antibody	Recombinant, ExactAb™, Validated, High Performance, See COA	ATP1A1	Plasma membrane reference
Ab120681	Recombinant PCNA Antibody	Recombinant, ExactAb™, Validated, 0.5 mg/mL	PCNA	Proliferation/cell-cycle marker
Ab120680	Recombinant PCNA Antibody	Recombinant, ExactAb™, Validated, High Performance, See COA	PCNA	Proliferation/cell-cycle marker
Ab091169	Recombinant beta III Tubulin Antibody	Recombinant, ExactAb™, Validated, High Performance, See COA	βIII Tubulin	Neural differentiation marker
Ab091154	Recombinant beta III Tubulin Antibody	Recombinant, ExactAb™, Validated, High Performance, 0.088 mg/mL	βIII Tubulin	Neural differentiation marker
Ab091155	beta III Tubulin Mouse mAb	Carrier Free, ExactAb™, Validated, High Performance, See COA	βIII Tubulin	Neural differentiation marker
Ab088446	Recombinant ACTA2 Antibody	Recombinant, ExactAb™, Validated, High Performance, 0.05 mg/mL	ACTA2	Smooth muscle/myofibroblast phenotype marker
Ab087247	Recombinant ACTC1/ACTA2/ACTG2 Antibody	Recombinant, ExactAb™, KD Validation, Validated, See COA	ACTC1/ACTA2/ACTG2	Actin-family-related detection
Ab091144	Recombinant beta I Tubulin Antibody	Recombinant, ExactAb™, Validated, High Performance, See COA	βI Tubulin	Microtubule-related reference
Ab132222	Recombinant Transferrin Antibody	Recombinant, ExactAb™, Validated, See COA	Transferrin	Secretion/transport-related detection

More loading control antibodies can be found in the “Loading Control Antibodies” category on the Aladdin website.

The selection of loading control antibodies should be based on reference protein stability, sample type, subcellular localization, and the detection system in order to establish a reliable internal experimental reference.

For more related articles, please see below:

[1] Principles of Western Blot Internal Reference Antibody Selection

[2] Aladdin® Loading Controls

[3] Guidelines of Primary Antibodies for Western Blotting

[4] Second Antibody Selection Guide