Characterization of a major brain tubulin variant which cannot be tyrosinated

Brain tubulin preparations contain an abundant type of tubulin which does not undergo the normal cycle of tyrosination-detyrosination, and whose nature is still unknown. We have used peptide sequence analysis and mass spectrometry combined with immunological procedures to show that this non-tyrosinatable tubulin has a specific primary structure. It differs from the tyrosinated isotype in that it lacks a carboxy-terminal glutamyl-tyrosine group on its α-subunit