[Sedoheptulose-1,7-diphosphate as a source of pentose phosphates in heart muscle]

A possibility and some peculiarities of phosphatase degradation of sedoheptulose-1,7-diphosphate in the myocardium has been demonstrated. The reaction products are inorganic phosphate and sedoheptulose-7-phosphate; the latter product is the substrate of the transketolase reaction during pentose phosphates production. The process is largely localized in the soluble fraction of heart cells; in cellular organelles it is represented in a lesser degree. Possible regulatory mechanisms of pentose phosphate biosynthesis in animal tissues are discussed.