 Depending on the body's state, ribulose 5-phosphate can reversibly isomerize to ribose 5-phosphate.Ribulose 5-phosphate can alternatively undergo a series of isomerizations as well as transaldolations and transketolations that result in the production of other pentose phosphates as well as fructose 6-phosphate and glyceraldehyde 3-phosphate (both intermediates in glycolysis).The enzyme ribose-phosphate diphosphokinase converts ribose-5-phosphate into phosphoribosyl pyrophosphate.