Sucrose-cleaving enzyme that provides UDP-glucose and fructose for various metabolic pathways. an NDP-alpha-D-glucose + D-fructose = a ribonucleoside 5'-diphosphate + H(+) + sucrose Fructose acts as a non-competitive inhibitor with an inhibition constant of 17.2 mM. In contrast, glucose inhibits uncompetitively with an inhibition constant of 4.3 mM. Homotetramer. Expressed in stems, in roots at different developmental stages, and in flower buds, flowers and maturing seeds, with the highest levels in strong utilization sinks for sucrose such as growing stems and tap root tips. Belongs to the glycosyltransferase 1 family. Plant sucrose synthase subfamily.