Tyrosination-detyrosination of the COOH-terminus of alpha-tubulin in oocytes and embryos of Bufo arenarum

Soluble tubulin from Bufo arenarum oocytes and early embryos was shown to be composed mainly of the non-tyrosinable species. The low proportion of tyrosinable tubulin was almost exclusively constituted by the tyrosinated form. Compared with oocytes and embryos, toad brain contained a higher proportion of tyrosinable tubulin constituted mainly by the non-tyrosinated form. Tubulin carboxypeptidase was detected in toad brain but not in oocytes and embryos.