Isoelectric Focusing

Isoelectric Focusing (IEF) performs in a particular pH gradient, in which proteins are separated by differences in their isoelectric points. The isoelectric point (pI) is the pH at which the net charge of the protein is zero. Protein is positively charged when its pI is above the solution's pH, so it migrates towards the cathode. Conversely, protein is negatively charged when its pI is below the solution's pH, so it migrates towards the anode. Protein has no net charge at its pl and stops migrating. Based on this principle, proteins can be separated into sharp bands with each protein positioned at a point in the pH gradient corresponding to its pI.

Fig.1 Illustration of isoelectric focusing

• Preparation
  Prepare the gel containing the sample. Mix the solution and add it to a glass tube to form a gel. Prepare the fixing solution, dyeing solution and decolorization solution.
• Electrophoresis
  Add the appropriate acidic solution in the positive electrophoresis tank, and the appropriate alkaline solution in the negative electrophoresis tank. Switch on the electrophoresis apparatus and set the voltage and current. Perform pre-electrophoresis for a period of time to form a pH gradient in the gel. Then set the electrophoresis apparatus to a higher voltage and perform electrophoresis for a period of time.
• Determination
  Different protein components focus on the corresponding pI. Fix, stain and decolorize the gel. Finally, dry it for storage.

• High resolution for better separation
• Applied electric field and pH gradient for minimized band spreading
• More separated bands than other methods
• Easy operation and sample treatment
• Less time consumption

• For research in taxonomy, enzymology, cytology and immunology
• Separation of peptides and proteins
• Study on the microheterogeneity of proteins
• Separation of isoenzymes
• Combination with 2D gel electrophoresis
• Separation and identification of serum proteins

Electrophoresis Systems

An electrophoresis system applies an electric charge to molecules, causing them to migrate toward their oppositely charged electrode. It’s the device for electrophoresis performing and is usually divided into horizontal type and suspension type. The choice of electrophoresis systems depends on the molecule of study, the method of separation and the downstream application.

Electrophoresis Accessories

We provide comprehensive electrophoresis accessories including electrophoresis power supplies, combs, UV blocking mats, exposure cassettes, gel cutting tools, short plates, spacer plates, and so on, for gel preparation and electrophoresis performance in electrophoresis experiments.

pH Meters

A pH meter is an instrument used to determine the pH value of a solution, utilizing the relationship between the electromotive force of the galvanic cell and the hydrogen ion concentration. A pH meter is used to determine the pH value of buffers in electrophoresis experiments. The temperature and ionic strength should be considered in pH measurement.

Pipettes

Pipettes are used to aspirate and dispense larger and specific amounts of liquid. They made be reusable or disposable, made from glass or plastic (typically polystyrene), nonsterile, sterile, or autoclavable, and cotton-plugged or plain. Accurate liquid measurements, dilutions, and transfer is key to most successful laboratory assays and analyses.

Staining Appliances

We provide Gel Staining Boxes made from translucent polypropylene or clear PMP with snap-fit lids. Drain located flush with the bottom minimizes disturbance of the gel during liquid drainage. The box can be used to stain, fix, destain and manipulate gels and membranes conveniently in electrophoresis experiments.

Gel Drying Equipment

We provide gel drying equipment with drying frames, assembly table, cellophane, gel drying solution, and other accessories to dry the microgel between two sheets of cellophane, for the preservation of polyacrylamide and agarose gels. Once dry, the gel is clear with a glossy finish and is ideal for use in density measurements or as a photographic record for long-term storage in a lab notebook.

STEMart provides you with a variety of electrophoresis equipment or consumables to meet your various R&D and application needs. If you have any questions or requirements for isoelectric focusing, please feel free to contact us.