Glossary

Electrophoresis

Analytical

Electrophoresis — A laboratory technique that separates molecules based on their size and charge by applying an electric field across a gel or capillary medium.

What Is Electrophoresis?

Electrophoresis is the migration of charged molecules through a gel or solution under an applied electric field. In peptide research, gel electrophoresis separates peptides and proteins by molecular weight (SDS-PAGE) or charge/size (native PAGE), providing a visual readout of sample composition, purity, and molecular weight confirmation complementary to HPLC and mass spectrometry.

Types Used in Peptide Research

SDS-PAGE: Sodium dodecyl sulfate denatures proteins and imparts uniform negative charge, enabling separation by size alone. Standard for Western blot sample preparation
Tricine-SDS-PAGE: Optimized for small peptides (2-20 kDa) using tricine as the trailing ion for better resolution in the low molecular weight range
Capillary electrophoresis (CE): High-resolution separation in narrow capillaries. CE is an orthogonal purity method to HPLC, required by some pharmacopeial monographs
Isoelectric focusing (IEF): Separates by isoelectric point (pI), useful for characterizing peptide charge variants

Detection Methods

Coomassie Blue (sensitivity ~100 ng), silver stain (~1 ng), or fluorescent stains (SYPRO Ruby). For peptides below 5 kDa, fixation with glutaraldehyde before staining prevents diffusion out of the gel.

Frequently Asked Questions

What is Electrophoresis?

A laboratory technique that separates molecules based on their size and charge by applying an electric field across a gel or capillary medium.

Why is Electrophoresis important in peptide research?

Electrophoresis is a fundamental concept in analytical as it relates to peptide science. It directly influences experimental design, compound characterization, and the reliability of research outcomes across biochemistry and molecular biology disciplines.

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