May play an important role in maintaining the flux of carbon towards starch formation in endosperm. May also be involved in a sugar-sensing pathway. ATP + D-fructose = ADP + D-fructose 6-phosphate + H(+) Strongly inhibited at high fructose concentration. Glycan biosynthesis; starch biosynthesis. Expressed in stem, sheaths, anthers, and panicles (at protein level). Belongs to the carbohydrate kinase PfkB family.