Key benefits of loading control antibodies

• Normalise protein levels across different samples using antibodies to housekeeping proteins to maintain consistent expression to have confidence in your experimental conditions.
• Ensure uniform loading and transfer of protein samples to have confidence in your results.
• Identify authentic biological differences in samples by eliminating technical variation.
• Whether you are studying drug treatment response or post-translational modifications, employing a reliable loading control antibody is key to differentiating genuine biological changes from variations due to technical factors.

Why choose loading control antibodies from St John's Laboratory

• Validated for Western blot and other immunodetection methods
• High lot-to-lot consistency
• Monoclonal and polyclonal options
• Multi-species reactivity
• Our antibodies are supported by comprehensive validation data

Cytosolic loading controls play a vital role in accurately interpreting Western blot results

Loading control antibodies serve as internal standards to confirm that variations in target protein levels are caused by experimental conditions rather than inconsistencies in sample loading or blotting technique. By providing a consistent baseline, these controls help distinguish true biological effects from technical artefacts.

Commonly used loading control antibodies target GAPDH, actin, and tubulin, which are highly expressed housekeeping proteins across most cell types and treatments, making them reliable loading control antibodies for Western blots.

• Beta-actin: A major component of the cytoskeleton, beta actin antibody is one of the most widely used loading control antibodies for western blot. Our anti beta actin antibody is validated for broad reactivity and provides consistent results.


• GAPDH: GAPDH is an excellent choice for a loading control antibody. Our GAPDH antibody selection includes unconjugated, conjugated (HRP, fluorescent), and species-specific options, giving you flexibility for multiple experimental protocols.


• Tubulin: The building block of microtubules, beta tubulin and alpha tubulin are popular loading control antibodies for studying the cytoskeleton. Our alpha tubulin antibody loading control and beta tubulin antibody products are verified for consistent expression.

Actin isoforms and antibodies: selecting the right tool for your research

Actins are a highly conserved family of six proteins that form the core of the cytoskeleton and play essential roles in cell structure, motility, division, and intracellular transport.

In vertebrates, there are six main actin isoforms, which can be categorised into muscle and non-muscle types. Each isoform has distinct expression patterns and biological functions, making it important to choose the appropriate one for your research needs.

HRP conjugated beta actin antibodies

Target	Conjugated beta actin primary antibodies
HRP conjugated beta actin antibody	Anti-ACTB antibody [S5764MM] {HRP} (STJ11105764)
Biotin conjugated beta actin antibody	Anti-ACTB antibody [5B7] {Biotin} (STJA0006201).

Fluorescently conjugated beta actin antibodies

Target	Conjugated beta actin primary antibodies
HRP conjugated GAPDH primary	Anti-ACTB antibody [S5764MM] {HRP} (STJ11105764)
Biotin conjugated beta actin primary antibody	Anti-ACTB antibody [5B7] {Biotin} (STJA0006201).

Plant specific beta actin antibodies

Target	Beta actin antibodies
Plant beta actin antibody	Anti-Actin-Plant Specific antibody (STJ11107558)
Plant beta actin antibody	Anti-Actin-Plant Specific antibody [SMM] (STJ11107554)

Alpha actin antibodies

There are four primary alpha actin isoforms, three of which are specifically expressed in various muscle tissues.

Anti-Actin, sarcomeric muscle antibody (2-50 aa) [ABT-SCA] (STJ197005 recognises both:

• Alpha-cardiac actin (ACTC1): primary actin found in the heart muscle.


• Alpha-skeletal actin (ACTA1): actin is a key component of skeletal muscles, which are responsible for voluntary movement.

Pan actin antibodies

• Anti-actin antibody (326-375 aa) (STJ91461)


• Anti-actin antibody (C-Term) (STJ13100007)

Tubulin antibodies

Enhance your research with our comprehensive selection of high-quality tubulin antibodies. Tubulins are the essential building blocks of microtubules, playing a crucial role in vital cellular processes like cell structure, division, and transport. Our extensive catalog includes a wide variety of antibodies targeting alpha, beta, and gamma tubulins, as well as pan-specific options.

Each antibody is rigorously validated to ensure reliable and reproducible results for a range of applications, including Western blotting, immunofluorescence, and immunohistochemistry. Find the perfect antibody to advance your cell biology and cytoskeletal research below.

Explore our range of tubulin antibodies categorised by their type.

GAPDH antibodies

Browse our range of antibodies available in different formats

Unconjugated GAPDH primary antibodies

• These are the most versatile antibodies, not pre-linked to any detection molecule.


• Gives you maximum flexibility to use your own choice of secondary antibody, allowing for various detection methods and signal amplification.

  Target	Unconjugated GAPDH primary antibodies
  GAPDH unconjugated primary	Anti-GAPDH antibody (Met1-Glu335) [1A201] (STJA0022030)
  	Anti-GAPDH antibody (STJ13100504)
  	Anti-GAPDH antibody (C-Term) (STJ13100140)

  
  

Conjugated GAPDH primary antibodies

• Antibodies directly linked to a fluorophore (e.g., DyLight®), enzyme (HRP), or Biotin.


• Simplify your protocol by removing the need for a secondary antibody step. Ideal for specific applications like Western blotting (HRP), multiplexing and immunofluorescence (fluorophores), or signal amplification (biotin).

  Target	Conjugated GAPDH primary antibodies
  DyLight conjugated GAPDH primary	Anti-GAPDH antibody (C-Term) {DyLight®800} (STJ140312)
  HRP conjugated GAPDH primary	Anti-Recombinant-GAPDH antibody [SR0718] {HRP} (STJA0010718)
  Biotin conjugated GAPDH primary	Anti-GAPDH antibody [2B8] {Biotin} (STJA0006060).

Species-specific GAPDH antibodies

Available in different formats

• GAPDH antibodies target both mammalian and non-mammalian organisms.


• We offer a range of antibodies targeting different non-mammalian models, such as yeast, fruit flies Drosophila melanogaster or C. elegans.

  Target	Species-Specific GAPDH antibodies
  Yeast	Anti-GAPDH-Yeast antibody (Full Length) (STJA0006713)
  Drosophila melanogaster	Anti-GAPDH-Drosophilidae antibody (Full Length) (STJA0006712)

  
  

Additional reagents for GAPDH antibody validation

Additional reagents for GAPDH antibody validation include blocking peptides used to confirm specific binding to the target protein:  GAPDH Blocking Peptide for STJ506148 peptide (STJ505877).

Positive control peptides for GAPDH verify the detection system.

Loading controls for mitochondrial fractions

Cadherin antibodies as immunofluorescence controls

Cadherin antibodies are excellent controls for immunofluorescence (IF), though they don't function as loading controls like those in Western blotting. Instead, they serve as crucial markers to confirm the antibody is binding to the correct cellular location and to identify specific cell types. Cadherins are especially useful because their expression is specific to certain cell-to-cell junctions and different cell populations.

E-cadherin antibodies are employed to visualise adherens junctions in epithelial tissues. Observing the antibody stain these specific junctions confirms the experimental procedure is working as expected. Similarly, cadherin antibodies can help researchers identify different cell types within a tissue sample, as E-cadherin is a known marker for epithelial cells, while N-cadherin identifies mesenchymal cells and neurons.

Other related products:

St John’s Laboratory also offer antibodies that target specific post-translational modifications (PTMs) on the control proteins, allowing you to study how their function changes in response to different conditions. They are distinct from the antibodies used to measure the total amount of the protein.

For specific modifications to control proteins, visit our website for more details on.

Alpha tubulin post-translational modifications

• Detyrosinated alpha-tubulin, use Anti-detyrosinated alpha tubulin antibody [1A047] (STJA0021739) or Anti-Detyrosinated alpha tubulin antibody [1A046] (STJA0021738)

• Acetylated alpha tubulin, use Anti-Acetyl-TUBA1A-K40 antibody (STJ11105006) to identify stable microtubules, helping researchers understand cellular processes like transport and disease mechanisms. Acetylated alpha tubulin antibody specifically recognises the acetylated form of alpha tubulin at lysine 40 (K40), which is a marker for the functional state of the cytoskeleton, distinguishing permanent structures from dynamic ones.

Phosphorylated forms of beta actin

Our Anti-Phospho-Beta Antibodies are ideal tools for researchers studying cell signalling and cytoskeletal dynamics. These highly specific antibodies allow you to precisely detect the activated, phosphorylated form of beta-actin, such as tyrosine 53 site, helping you investigate key processes like cell motility and disease mechanisms (e.g. cancers and muscular dystrophies). Optimised for use in techniques such as Western blotting and immunocytochemistry, they provide a reliable and efficient way to advance your research.

Learning and Support

Loading Control Antibody Guide

Beta Actin – What’s so special about it?