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  • 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).

    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 72.5
    58 48 48 45 52
    46 35 35.5 35 40.5
    30 27 25 25 n/a
    25 24 17 17 n/a
    17 19 12.5 12 n/a
    7 13 9 7.5 n/a