Polyacrylamide (PAGE)
Definition
Cross-linked synthetic gel with tunable, smaller pore size. Used for proteins and small DNA fragments.
- Matrix type
- Cross-linked synthetic polymer gel
- Pore size
- Small, tunable via acrylamide concentration
- Typical use
- Proteins and small DNA fragments
- Contrast
- Finer resolution than agarose gels
Common questions
Why choose PAGE over agarose electrophoresis?+
Agarose pores are too large to separate proteins or short DNA fragments that differ by only a few bases, while polyacrylamide's smaller, adjustable pore size resolves those fine size differences.
What limits how large a fragment PAGE can run?+
The same small pore size that gives PAGE its resolution restricts large fragments from migrating well, so agarose remains the practical choice once fragments run into the thousands of base pairs.
Related terms
- Agarose
- Polysaccharide gel from seaweed. Large pore size, used for nucleic acids and large proteins. Standard for DNA submarine gels.
- Capillary Electrophoresis (CE)
- A separation technique that resolves DNA fragments by size through a polymer-filled glass capillary under an applied electric field. Single-base resolution is...
- Electrophoretic Mobility (μ)
- Velocity of a charged particle per unit electric field, μ = v/E. Depends on charge, size, shape and the viscosity of the...
- IEF (Isoelectric Focusing)
- Electrophoresis across an immobilised pH gradient. Each protein migrates until it reaches its pI and stops. Very high resolution; used in haemoglobin...
- Immunoelectrophoresis
- A two-step technique: proteins are first separated by electrophoresis in agar gel, then antiserum diffuses from a parallel trough and forms precipitin...
- Isoelectric Point (pI)
- pH at which a molecule (usually a protein) carries zero net charge and stops migrating. The basis of isoelectric focusing (IEF).
- Precipitin Arc
- Curved line of antigen-antibody precipitate that forms at equivalence in immunoelectrophoresis. Shape and position identify the antigen.
- SDS-PAGE
- PAGE run with sodium dodecyl sulphate. SDS coats proteins with uniform negative charge, so separation is by molecular weight alone.