Bio-Rad Model 491 Prep Cell and Mini Prep Cell - Manual (Page 25)

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The larger gel surface of the 37 mm tube also allows for greater sample loads than does the 28 mm tube.
Tighter bands can be maintained by distributing the protein over a larger area.
Refer to Table 2 to determine the correct tube size and gel length for your purifica tion scheme.
The following guidelines are established for optimizing resolution and re covery of the protein of interest with
the least amount of dilution. The rec ommended protein loads in Table 2 refer to the amount of protein of
inter est and its nearest contami nant, not the total protein load. The tables also provide the monomer
volumes re quired for the recom mended gel length.
Table 2. Small gel tube (28 mm ID).
∆MW
(a)
Protein Load
(b)
Monomer Volume
(c)
Gel Length
>15% <1 mg 20 ml 4–6 cm
>15% 1–2 mg 20–40 ml 4–6 cm
>15% >2 mg proceed to table 3 –
10–15% <0.75 mg 20 ml 4–6 cm
10–15% 0.75–1.5 mg 20–40 ml 6–10 cm
10–15% >1.5 mg proceed to table 3 –
2–10% <0.5 mg 20 ml 4–6 cm
2–10% 0.5–1 mg 20–40 ml 6–10 cm
2–10% >1 mg proceed to table 3 –
Table 3. Large gel tube (37 mm ID).
∆MW
(a)
Protein Load
(b)
Monomer Volume
(c)
Gel Length
>15% <2 mg 50 ml 6 cm
>15% 2–4 mg 50–100 ml 6–10 cm
>15% >4 mg 100 ml 10 cm (d)
10–15% <1.5 mg 50 ml 6 cm
10–15% 1.5–3 mg 50–100 ml 6–8 cm
10–15% >3 mg 80 ml 10 cm (d)
2–10% 1 mg 50 ml 6 cm
2–10% 1–2 mg 50–100 ml 6–10 cm
2–10% >2mg 110 ml 10 cm (d)
(a) ∆MW refers to the percentage difference in size between the protein of interest and its near est con taminant.
(b) Protein load refers to the combined amount of the protein of interest and its nearest contam i nant and is
independent of the total protein load.
(c) The monomer volume recommended is based on using the optimum %T as established from analyti cal
gels.
(d) Loads greater than the recommended amounts may lead to corresponding loss of resolution.
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