The enzymic determination of energy-rich phosphates in brain

Abstract

The spectrophotometric method of phosphate analysis developed by Slater (ibid 53: 157. 1953) was adapted for the detn. of energy-rich phosphates in mammalian cerebral tissues. It is based on the enzymic formation of dihydroxyacetone-phosphate and its enzymic reduction by reduced diphospho-pyridine nucleotide. Assays by this method gave values for creatine-phosphate which were in close agreement with those obtained by a chemical method. The adenosinediphosphate (ADP) and adenosinetriphosphate content of cerebral prepns. detd. enzymically were less than those detd. by the chemical method. Only traces of ADP could be found in cerebral cortex in vivo or in slices respiring in a glucose-containing saline. Creatine-phosphate, adenosinepolyphosphate and inorganic phosphate were measured in cerebral cortex slices maintained under a variety of metabolic conditions.