Yeast pheromone alpha-factor is synthesized as a high molecular weight precursor

The sex pheromone alpha-factor of Saccharomyces cerevisiae, a tridecapeptide of approx. 1,700 molecular weight, was found to be synthesized in vivo as a high molecular weight precursor of Mr = 28,000. Inhibition of N-linked glycosylation by tunicamycin leads to three precursor species of lower molecular weight indicating three carbohydrate residues linked to the alpha-factor precursor molecule. A molecular weight of 18,000 was determined for the unglycosylated molecule.