Localization and secretion of β-1,3-glucanase of cultured carrot cells

The β-1,3-glucanase of cultured carrot cells is found mainly in the soluble and cell wall fractions. The intracellular enzyme showed some affinity for concanavalin A and appeared to contain a mannose-rich carbohydrate moiety, while the cell wall-associated enzyme extracted by NaCl showed only a low affinity for the lectin. Secretion of the enzyme was inhibited by the addition of monensin suggesting that the enzyme is secreted via the Golgi body to the cell wall while the addition of tunicamycin did not show any significant effect on the biosynthesis and secretion into the cell wall matrix. These observations suggest that the carbohydrate moiety of the enzyme glycoprotein plays no important role in the transport and secretion of the wall-bound β-1,3-glucanase.