VI1 — Sorghum bicolor

Summary

SbVI1 (SORBI_3004G004800) on sorghum chromosome 4 encodes a beta-fructofuranosidase (invertase) with domains characteristic of glycosyl hydrolase family 32, including the N-terminal and catalytic domains. The enzyme exhibits beta-fructofuranosidase, 1,2-beta-fructan 1F-fructosyltransferase, sucrose 1F-fructosyltransferase, and 6G-fructosyltransferase activities. It is associated with sucrose and carbohydrate metabolism, specifically sucrose anabolism, and is linked to fructan biosynthesis through the reaction sucrose+sucrose→1-kestotriose+beta-D-glucose. The protein localizes to the vacuole, including the vacuolar lumen and membrane. Studies of related genes in other species link the family to additional fructosyltransferase activities (EC 2.4.1.100, 2.4.1.99, 2.4.1.243) and beta-fructofuranosidase activity (EC 3.2.1.26).