Isolation and partial characterization of α and β tubulin from outer doublets of sea urchin sperm and microtubules of chick embryo brain

Two kinds of tubulin (α and β) are described in microtubules from many different systems. In this study a discontinuous acrylamide gel system containing sodium dodecyl sulfate was used to separate milligram quantities of α and β tubulin from microtubules of chick embryo brain and from outer doublets of sea urchin sperm. The isolated tubulins were characterized by peptide mapping and automated sequencing of the first 25 NH₂ terminal amino acids. The authors' results show that α and β tubulin are related but distinctly different proteins and that each one has been highly conserved in the course of evolution.