Kinesin heavy chain from bovine brain and Drosophila appear to be highly homologous molecules

A microtubule‐enriched fraction was prepared from bovine white matter, and kinesin and other microtubule‐associated proteins were extracted from taxol‐stabilized microtubules by homogenization and ultracentrifugation in the presence of nucleotides (guanosine triphosphate and adenosine triphosphate). The kinesin‐enriched fractions were subjected to preparative SDS‐PAGE, and the band representing the kinesin heavy chain was excised, homogenized, and subjected to partial enzymatic digestion with Staphylococcus aureus V8 protease. Four peptides were selected for sequence analysis and compared to the previously published sequence for the Drosophila kinesin heavy chain (Yang JT, Laymon RA, Goldstein LSB, Cell 56:879–889, 1989). All four peptides matched closely with portions of the Drosophila sequence corresponding to the central, α‐helical domain. Total amino acid composition analysis of bovine kinesin heavy chain also reveals a high degree of homology to the Drosophila sequence.