The molecular weight (MW) of a protein can be predicted based on its amino acids (AA) composition. However, in many cases a non-chemically modified protein shows an SDS PAGE-displayed MW larger than its predicted size. Some reports linked this fact to high content of acidic AA in the protein.
This online tool could used to estimate the difference between theoretically predicted and SDS PAGE-displayed molecular weights for an acidic protein.
1. Sequence (Paste the raw sequence, not fasta format):
Absorbance and Extinction Coefficients
The difference between the predicted and SDS PAGEdisplayed MW showed a linear correlation with the percentage of acidic AA that fits the equation y = 276.5x − 31.33 (x represents the percentage of acidic AA, 11.4% ≤ x ≤ 51.1%; y represents the average ΔMW per AA).
- 1. Guan, Y., Zhu, Q., Huang, D. et al. An equation to estimate the difference between theoretically predicted and SDS PAGE-displayed molecular weights for an acidic peptide. Sci Rep 5, 13370 (2015). https://doi.org/10.1038/srep13370.