Lectin Affinity as an Approach to the Proteomic Analysis of Membrane Glycoproteins

The aim was to determine the proportion of membrane glycoproteins captured using concanavalin A
or wheat germ agglutinin lectin affinity chromatography. Digests of the isolated proteins were separated
by reversed-phase liquid chromatography and analyzed by matrix-assisted laser desorption tandem
mass spectrometry. The two lectins identified different groups of proteins with a broad range of
molecular mass and pI values, including a number of proteins that overlapped the two groups.
Approximately 30% of the proteins were positively identified as containing domains that were predicted
using standard bioinformatics methods to be characteristic of integral membrane proteins. This approach
represents an effective method of surveying the membrane protein pool of mammalian cells for
subsequent proteomic analysis.
Keywords: membrane proteins • transmembrane • MALDI MS/MS • lectin affinity chromatography • Con A • WGA
• glycoproteins