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Updated: May 19, 2026

Robust Comparison of Protein Levels Across Tissues and Throughout Development Using Standardized Quantitative Western Blotting
Published on: April 9, 2019
A regularly spaced and self-revealing protein ladder for anti-tag Western blot analysis
Chien-Han Kao1, Chiu-Min Cheng, Kuo-Hsiang Chuang
1Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Abstract:
We designed a protein ladder (hereafter referred to as "Mega-tag") that contains 14 of the most commonly used epitope tags fused to molecular weight markers. The Mega-tag ladder can be simultaneously visualized when anti-tag antibodies are used to detect epitope-tagged recombinant proteins in Western blots. The logarithm of molecular weights and relative mobility of the Mega-tag protein ladder are highly correlated (R(2)=0.997±0.00232), indicating that the dye-free Mega-tag protein ladder is accurate. It can also serve as a positive control for anti-epitope tag immunoblots. The Mega-tag protein ladder should provide a convenient and precise tool for Western blot analysis.
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