Bio-Rad Profinity IMAC Resins - Manual (Page 15)

The following procedure provides a quick screen for
solubility and expression level:
1. Pellet ~ 2 ml of E. coli culture by centrifugation
at 4,000 x g for 10 min at 4°C.
2. Resuspend the pellet in 500 µl of PBS and
sonicate for 60 sec, on ice, in 10 sec pulses.
Remove 50 µl of the sonicate and label as the
"Total" sample. Centrifuge the lysate at
12,000 x g for 10 min at 4°C. Transfer the
supernatant to a clean tube. Remove 50 µl of
the supernatant, and label tube "Soluble".
3. Resuspend the insoluble pellet in 500 µl of 6 M
urea in 1x PBS and sonicate for 60 sec, on ice,
in 10 sec pulses. Centrifuge the lysate at
12,000 x g for 10 min at 4°C. Remove 50 µl of
the supernatant, and label "Insoluble".
4. To each of the 50 µl samples, add 150 µl of
Laemmli buffer, and boil for 5 min at 95°C.
5. Load 10 µl of each sample on an SDS-PAGE
gel.
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