The first stable product of CO2 fixation in C3 plants is a three-carbon organic acid. The enzyme ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO) combines CO2 with the ribulose 1,5-bisphosphate to form two molecules of 3-phosphoglyceric acid. Related Theory ADP,NADP, and glucose are the end products of the C3 cycle. ADP and NADP are produced in the first stage of C3 cycle. In the second stage, glucose is produced.