Bio-Rad Bio-Gel P Polyacrylamide Gel - Manual (Page 5)

1.4 Storage Conditions
All unopened Profinia IMAC purification and buffer kits can be stored
between 4 and 22°C. The GST kits can be stored at 22°C for up to two
weeks. For long-term storage, the GST kits should be stored at 4°C. The
labels on the outside of the kit box provide exact expiration dates.
Section 2
Native IMAC Purification and Buffer Kits
2.1 General Buffer and Cartridge Information
The buffers provided in the native IMAC kit are formulated from
potassium salts and buffers, and contain increasing concentrations of
imidazole for optimized binding, washing, and eluting of histidine (His)-
tagged proteins. Native IMAC buffers* are used for proteins that
partition into the soluble fraction of
Escherichia coli lysates and that have
accessible His sequence tags. Table 2 provides a list of buffer compositions.
The native lysis buffer, the same as wash buffer 1, is used for sample
preparations (see Section 6), and is not used in any of the instrument
ports.
The IMAC cartridges are shipped in 20% ethanol and can be stored
between 4 and 22°C prior to use. The cartridges are packed with 1 ml of
Bio-Rad's Profinity™ IMAC resin, and typically yield 10 mg of purified
protein per run (dependent upon protein expression level and culture
volume loaded). To minimize any possibility of cross-contamination, it is
suggested that individual cartridges be dedicated to the purification of a
unique His-tagged protein. The desalting cartridges are provided in 20 mM
Bis-Tris, pH 6.5 with 0.05% azide as a preservative and can be stored
between 4 and 22°C prior to use.
* IMAC buffers made with potassium salts do not form precipitates with long-term storage.
However, to prevent the formation of insoluble potassium-SDS complexes in Laemmli buffer,
native IMAC samples and fractions (lysate load, flowthrough, wash 1, and wash 2 samples) should
be diluted at least 1:7 in Laemmli buffer prior to electrophoresis. The desalted and purified fraction
is collected in a PBS-based buffer and only needs dilution 1:2 prior to electrophoresis.
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