My protein shows single band at 28Kda in SDS-PAGE but for MALDI it shows a single peak at 23 Kda what could possibly be the reason
Accuracy of MW determination by SDS-PAGE with calibration curve is about 10% (http://www.jbc.org/content/244/16/4406). Did you created calibartion curve or estimated visually? Some PTMs can affect mobility of protein in SDS-PAGE. The same protein (with disulphide bonds) in reduced and non-reduced states will have different "apparent molecular weigts" due to differneces in shape of the molecule. MS is more reliable method for determination of MW, while SDS-PAGE should be used for rough estimate.
Accuracy of MW determination by SDS-PAGE with calibration curve is about 10% (http://www.jbc.org/content/244/16/4406). Did you created calibartion curve or estimated visually? Some PTMs can affect mobility of protein in SDS-PAGE. The same protein (with disulphide bonds) in reduced and non-reduced states will have different "apparent molecular weigts" due to differneces in shape of the molecule. MS is more reliable method for determination of MW, while SDS-PAGE should be used for rough estimate.
Sergey is right. In turn, SDS-PAGE mobility depends on the size and the shape of the protein, but also on other factors. For instance glycoproteins behave different when forming the SDS micelle. For MW determination, MALDI is much more accurant than SDS.PAGE. No doubt
MALDI is more accurate as SDS depend on different factors ie size , shape , rduced disulphide bonds.
- Badges
- Science method