The homologue of the mammalian coatomer complex was isolated from yeast cytosol and separated on a modified urea-containing SDS-polyacrylamide gel system. An additional band in the 100 kDa molecular weight range appeared when compared to the protein pattern obtained in conventional Laemmli gels, exactly as observed for mammalian coatomer. Cross-reactivity with an anti-peptide antibody raised against the C-terminus of β-COP from bovine, and N-terminal sequence analysis, revealed that this protein from yeast is related to β-COf from mammals.
