ABSTRACT
Some of the electrons of high reducing potentials (belonging actually to systems possessing strongly negative values of reducing potentials) must be actually conserved for biosynthesis instead of being transferred to dioxygen to form ATP. All these possibilities are respected by the pentose phosphates pathway. In the pentose phosphates pathway, NADPH is formed when glucose-6-phosphate is oxidized to ribulose-5-phosphate in the oxidative part. Neoglucogenesis is essential since the supplies of glucose from its natural stores are not always sufficient even in physiological conditions, for example, after a vigorous exercise. As a rule, given the facts that in the glycolysis the glucose is transformed into pyruvate and that during the neoglucogenesis the pyruvate is transformed in glucose, one would imagine that the neoglucogenesis is exactly the inverse of glycolysis. It is not the truth. The supplementary cost of the neoglucogenesis is, hence, of four energy-rich phosphate bonds per glucose molecule synthesized from pyruvate.
