Total protein staining with Congo red as an alternative loading control for western blot analysis

Area of Science:

• Biochemistry
• Molecular Biology
• Proteomics

Background:

• Western blot analysis commonly uses housekeeping proteins (e.g., β-actin, glyceraldehyde-3-phosphate dehydrogenase) as loading controls.
• These internal controls can exhibit variability across different cell states and tissue types, limiting their reliability.
• Existing controls are unsuitable for samples like serum, extracellular secretions, or cerebrospinal fluid, and for protein purification.

Purpose of the Study:

• To investigate total protein measurement using Congo red staining as a superior alternative to conventional loading controls in western blotting.
• To evaluate the cost-effectiveness, technical simplicity, and accuracy of Congo red staining for protein quantification.

Main Methods:

• Western blot analysis was performed.
• Total protein was quantified using Congo red staining.
• Comparison of Congo red staining with traditional housekeeping protein controls was conducted.
• Linear regression analysis was used to assess accuracy.

Main Results:

• Congo red staining demonstrated a superior performance compared to routine loading controls.
• This method offers advantages in terms of lower cost and technical simplicity.
• Improved linear regression indicated enhanced accuracy in protein quantification.
• Congo red staining is suitable for a broader range of sample types than traditional controls.

Conclusions:

• Congo red staining is a reliable and advantageous method for total protein measurement in western blots.
• It serves as a superior alternative to internal loading controls, especially for diverse sample matrices.
• The study proposes the adoption of Congo red staining for consistent protein loading evaluation in immunoblotting.