Home FAQs Why do the apparent molecular weight values for the prestained protein markers appear to be different in different gel types?

FAQ: Why do the apparent molecular weight values for the prestained protein markers appear to be different in different gel types?

When a protein is covalently bound to a charge-carrying dye molecule, this can affect the protein's overall charge. Altering the protein’s charge will most likely change its mobility within the gel. This explains why the prestained protein markers are given "apparent" molecular weight values, while regular unstained protein markers are given their true molecular weights. The apparent molecular weights state on the data cards and other references of our prestained protein markers were determined using 10-20% Tris-Glycine gels. It has been observed that when run on different gel types (Tris-tricine, Bis-Tris, etc), the apparent molecular weight seems "incorrect". The reason for this disparity is the different formulations of the gel types (buffering agents, ionic strength and pH).

Color Plus Prestained Protein Marker - apparent molecular weights:
10-20%
Tris-glycine		 10-20%
Tris-tricine		 4-12%
Bis-Tris (MOPS)		 4-12%
Bis-Tris (MES)		 3-8%
Tris-acetate
175 141 138 126 148
80 66 66 63 69
58 48 48 45 52
46 35 35.5 35 40.5
30 27 25 25 n/a
23 24 17 17 n/a
17 19 12.5 12 n/a
7 13 9 7.5 n/a