Processing of yeast exoglucanase (β‐glucosidase) in a KEX2‐dependent manner

Abstract
We have detected proteolytic processing of a form of exoglucanase representative of the endoplasmic reticulum (form A). This processing did not take place when form A was obtained from protoplasts lysed in the presence of either EDTA or leupeptin, two wel‐characterized inhibitors of KEX2 endoprotease from Saccharomyces cerevisiae. Sequencing of the amino terminus of an A‐like form of enzyme secreted by a kex2 mutant indicated the presence of 4 amino acids, with a pair of basic residues (Lys‐Arg) at their carboxyl side, preceding the amino terminus of the wild‐type external exoglucanase.