Export of an invertase by yeast Candida utilis cells

Export and accumulation of various forms of invertase (EC 3.2.1.26) in the cell wall and culture medium of the yeast Candida utilis was investigated. It was found that there is the high-molecular-weight invertase in the cell wall (CW-form). This form is not exported into the culture medium, and it is by a third more glycosylated than the previously described exported S-form. It was shown that one of the two forms of invertase exported into the culture medium—the glycosylated S-form—is retained in the cell wall, while the other one-the nonglycosylated F-form—was not detected in the cell wall. Based on these results, as well as data on the distribution dynamics of the enzyme in the culture medium and in the cell wall during different growth stages of a yeast culture, we suggested that the nonglycosylated form was exported into the culture medium via the zone of abnormal cell wall permeability and the glycosylated forms of this enzyme (both exported and nonexported) did not use this pathway and the degree of N-glycosylation is an important factor determining the final localization of the enzyme.