Pentose phosphate pathway (PPP) produce NADPH which is utilized for fatty acid synthesis, cholesterol synthesis, and steroid biosynthesis, and redox maintenance, and ribose 5-phosphate which is necessary for synthesis of nucleic acid. It is known that alternative pathway of PPP from glucose to 6-phosphogluconate exists in bacteria, however, it remains unclear in animals. In our previous study, SMP30/gluconolactonase (GNL) hydrolyzed glucono 1,5-lactone to gluconate, and gluconokinase (GNK) catalyzed phosphorylation of gluconate to 6-phosphogluconate in human and mouse. To reveal tissue distribution of GNK in mouse, we measured protein levels of SMP30/GNL and GNK in alternative PPP, and glucose 6-phosphate dehydrogenase (G6PD) in PPP.

Six C57BL/6J male mice were dissected at 8 weeks of age, and 19 kinds of tissues were collected. Protein levels of SMP30/GNL, GNK, and G6PD were quantified by Western blot analysis.

Both of SMP30/GNL and GNK protein was highly expressed in liver, duodenum, and kidney. G6PD protein was highly expressed in epididymal fat, subcutaneous fat, adrenal gland, and brown fat. Overall, the tissue distributions of protein level were similar between SMP30/GNL and GNK, which was distinct from that of G6PD. These results suggest that SMP30/GNL and GNK could cooperatively functions in alternative PPP, and physiological role of alternative PPP might be different from that of PPP. Immunohistochemical staining of SMP30/GNL, GNK, and G6PD in tissues are now in progress.