Bio-Rad PROTEAN® IEF Cell Accessories - Manual (Page 3)

Section 1
Introduction
1.1 Overview
The Cup Loading Tray for the PROTEAN IEF cell is designed for the optimal resolution and
separation of proteins with isoelectric points (pI) at either extreme of the pH range. The Cup
Loading Tray can accommodate up to 12 IPG strips from 7 cm to 24 cm in length.
The Cup Loading Tray includes a tray base, a pair of movable electrode assemblies, and one bag
each (120 count) of 100 and 150 µl sample cups. No modifications to the PROTEAN IEF cell are
needed for compatibility with the Cup Loading Tray.
The Cup Loading Tray offers the following benefits:
• Enhanced resolution and separation of proteins with pIs at extreme pH ranges
• Optimal focusing for users of ReadyStrip™ IPG strips pH 3-6, pH 7-10, and Micro-range
ReadyStrip IPG strips pH 6.3–8.3
• Tray runs up to 12 IPG strips per run for high throughput
• Tray accommodates 7 cm to 24 cm IPG strips with movable electrode assemblies
• Two sample cup sizes, 100 and 150 µl, are available to allow greater flexibility
• The Cup Loading Tray is compatible with all PROTEAN IEF cells, so no modification to
existing PROTEAN IEF cell is necessary.
1.2 Introduction
Isoelectric focusing of proteins in the acidic and basic pH ranges is often associated with
streaking due, in part, to protein precipitation when utilizing standard in-gel rehydration of IPG
strips. Protein resolution can be markedly improved when the proteins are applied to the IPG
strips by means of a sample cup positioned in a discreet area of a rehydrated IPG strip.
The Cup Loading Tray allows for sample application via cup loading after rehydration of the IPG
strips. Certain conditions make cup loading the preferred method of sample loading. The
examples below compare in gel rehydration resolution with cup loading resolution of an E. coli
sample on pH 3-6 and pH 7-10 IPG strips.
1