Mobilization of the Galactomannan-contaioing Cell Walls of Tomato Seeds: Where Does beta-Mannosidase Fit into the Picture?

摘要

The major cell wall components of the endosperm that surround the embryo in seeds of tomato (Lycopersicon esculentum Mill.) are galactomannans (Groot et al., 1988). Three enzymes are involved in their hydrolysis: endo-beta-mannanase (EC 3.2.1.78), anendo-hydrolase that cleaves the mannan backbone; alpha-galactosidase (EC 3.2.1.22), which simultaneously removes the galactose side chains; and beta-mannosidase (also called beta-mannoside manno-hydrolase or exo-beta-mannanase, EC 3.2.1.25) which releases mannose from oligomers produced by prior endo-beta-mannanase activity (McCleary, 1982).