Abstract
Cva (C-terminal variable acidic amino acid region) of α, β-tubulins consists of the isotype-specific sequence which is extremely rich in acidic amino acids. Peculier modifications as tyrosinylation, polyglutamylation and polyglycinylation on Cva are reported as well as phosphorylation. We analysed β-tubulin isoform spots of IEF by MALDI-TOF MS, and recognized that each IEF spot did not necessarily consist of a single isoform, but might be a mixture of modified isotypes. The advantage of MALDI-TOF MS is that samples less than picomol which are not fully purified could be detected and their sequence could be analysed by PSD or with the use of CPY. Peptides derived from Cva are however, rich in acidic amino acids and may contain phosphate group and so, are relatively difficult to detect. We have examined preparation and detection conditions for Cva peptides and obtained partial information about post-translational modifications of β-tubulin isotypes in synchronized BY2 cells.
