User guide
Protein Molecular Weights
The molecular weights of every lot of
prestained standards are individually calibrated
against Bio-Rad’s SDS-PAGE Standards. The
lot specific calibrated molecular weights are
included with every vial. Prestained standards
are useful for estimating the molecular weights
of sample proteins, however, for precise molec-
ular weight determination, use Bio-Rad’s SDS-
PAGE, Silver Stain SDS-PAGE, or
Biotinylated SDS-PAGE Standards in addition
to the prestained standards.
Constituent Proteins
(See enclosed insert for lot specific
calibrated molecular weights.)
†
Protein Source
Myosin Rabbit skeletal muscle
ß-galactosidase E. coli
Bovine serum albumin Bovine plasma
Ovalbumin Chicken egg white
† Covalently bound dye alters the molecular weight of the
proteins and produces relatively broad bands. The molecular
weights are calibrated from the center of each protein band.
34
5 6
Myosin
β-galactosidase
Bovine serum
albumin
Ovalbumin
Instructions for Use
Heat the solution to 40 °C for 1 minute
to dissolve any solids which may have pre-
cipitated at -20 °C. To visualize the
prestained standards after blotting, load 10 µl
for full size gels (16-20 cm) and 5 µl for
mini gels. To visualize the standards during
electrophoresis, load 20 µl for full length
gels and 10 µl for mini gels. To see the stan-
dards during the run, it is helpful to hold a
sheet of white paper behind the gel.
Note
The prestaining of the proteins substan-
tially inhibits them from being further stained
with biotin/avidin systems, colloidal gold,
Coomassie R-250, or amido black. The stan-
dards can be silver stained, but silver staining
will result in broad bands because of the large
amount of protein in the sample.
Fig. 1. High Range Prestained SDS-PAGE Standards.
5 µl of the standards were run on a 7.5% SDS poly-
acrylamide gel according to the method of Laemmli.
1
The standards were run on the Mini-PROTEAN
®
II cell
and electrophoretically transferred to nitrocellulose
using the Mini Trans-Blot
®
cell.
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