Hi Giant Lee . This could be due to difference in glycosylation.

Hi Steingrimur Stefansson and Yuhta Nomura ,thank you very much. I once thought it was due to glycosylation, but please pay attention to the MW of light chains of the first two antibodies, they are apparently smaller than predicted 25KDa. Other than the first two antibodies, the light chain of the third one is larger than 25KDa, which may be due to glycosylation.

And I want to say, I have many other antibodies, most of them have light chains larger than 25KDa. So, I think the 2 with smaller light chain is abnormal which I can't explain.

Thanks again.

Hi Giant Lee . Mobility of proteins in SDS-PAGE assumes that SDS binds equally to all unfolded proteins, making them all negatively charged.

Ideally, large proteins bind lots of SDS, smaller proteins bind less SDS. But they should all have the same X number of SDS molecules bound to Y number of peptide bonded AA.

When run through a charge-neutral polyacrylamide mesh by electrophoreses , in theory, it is only the protein size going through that mesh that dictates mobility.

For the most part this works well, until you get into very basic proteins (with high Arg, Lys concentrations) very acidic proteins (with high Asp, Glu concentrations) or glycosylated proteins. Sugars don't bind SDS like peptides

They bind SDS like other proteins, but their overall charge after binding SDS makes them run higher or lower on SDS-PAGE than reflected by their AA composition.

Check https://www.promega.com/resources/tools/amino-acid-chart-amino-acid-structure/

Check on this paper.

https://www.ncbi.nlm.nih.gov/books/NBK21589/

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Hi Kiprotich Kiptum . Maybe you could get more upvotes if you post links to catalogs like Chinaza Godswill Awuchi . Increasing your RG scores by boosting isn't hard, you just need the right friends.