Bio-Rad Model 491 Prep Cell and Mini Prep Cell - Manual (Page 6)

Section 1
General Information
1.1 Introduction
The Model 491 prep cell* is de signed to purify proteins or nucleic acids from complex mixtures by
contin uous-elu tion electrophoresis. Conventional gel elec trophoresis buffer sys tems and media are used
with the prep cell.
During a run, samples are electrophoresed through a cylindri cal gel. As molecules migrate through the gel
matrix, they separate into ring shaped bands. Individual bands migrate off the bottom of the gel where they
pass di rectly into the patented elution chamber for collection.
The elution chamber consists of a thin polyethylene frit. A dialysis membrane, directly underneath the elution
frit, traps proteins within the chamber. Elution buffer enters the chamber around the perimeter of a specially
designed gasket. The unique design of the gasket results in an even flow of buffer into the elution frit. Buffer
is drawn radially inward to an elution tube in the center of the cooling core. Purified molecules are drawn up
through the elution col lec tion tube at the cen ter of the cooling core by a peristaltic pump. The peristaltic
pump drives sepa rated pro teins through a UV monitor (optional) to a fraction col lector (Bio-Rad's Econo
™
system).
To assure that separated molecules migrate in compact, paral lel bands, temperature gradients across the
gel are minimized. The temperatures of the internal and exter nal surfaces of the gel are equalized by
continuously pumping lower electrophoresis buffer through the central cooling core by means of the buffer
recirculation pump.
Simple procedures are provided for determining optimal running conditions for most purifications. It is
recommended that these procedures be performed for each new sample to be purified before proceeding to
a preparative run with the Model 491 prep cell.
1.2 Accessory Equipment
Power supply — 500 volt
Warning: Use only power supplies with isolated ground such as Bio-Rad's PowerPac
™ HV or
PowerPac Universal
Buffer recirculation pump — (provided with the prep cell
Peristaltic pump (elution pump)*
Fraction collector*
UV monitor
Chart recorder**
* U.S. patent number 4,877,510
** The use of a reliable fraction collector is essential for the isolation of the de sired component of the sample. It may also be convenient
to monitor elution by UV ab sorbance. To simplify setup and operation of accessory equipment, we recom mend use of Econo system
low pressure chromatography components, in cluding peri staltic pump, fraction collector, UV monitor, and chart recorder.
1