Metabolic labeling with amino acids.

Metabolic labeling techniques are used to study the biosynthesis, processing, intracellular transport, secretion, degradation, and physical-chemical properties of proteins. This unit provides protocols for metabolic labeling of cells with [(35)S]-labeled amino acids to provide material suitable for analysis by immunoprecipitation, for characterization of cellular proteins, for analysis of protein trafficking, and for one- and two-dimensional gel electrophoresis. Three procedures are described for suspension and adherent cells: pulse-labeling, pulse-chase labeling, or continuous long-term labeling. A support protocol describes TCA precipitation to measure the extent of labeling.