A rapid and convenient chemical assay for the enzyme d-glucose 6-phosphate-1l-myoinositol 1-phosphate cyclase is described. The 1l-myoinositol 1-phosphate formed enzymically was oxidized with periodic acid liberating inorganic phosphate, which was assayed. myoInositol 2-phosphate can be assayed in the same way. Glucose 6-phosphate and other primary phosphate esters gave only very small quantiti...

Inorganic phosphate, which is generated during osteoblast differentiation and mineralization, has recently been identified as an important signaling molecule capable of altering signal transduction pathways and gene expression. A large scale quantitative proteomic investigation of pre-osteoblasts stimulated with inorganic phosphate for 24 h resulted in the identification of 2501 proteins, of wh...

Changes in high-energy phosphate metabolism may be important in the regulation of myocardial contractile function during ischemia. This study sought to determine the dynamic relation between myocardial contractile function and high-energy phosphate metabolism during and following brief (24-second) coronary occlusion, when large and rapid changes in both parameters occur. Eight anesthetized, ope...

1. Thymectomy in young rabbits decreased the ATP content and increased the inorganic phosphate content of skeletal muscle. The serum calcium content was decreased, whereas the inorganic phosphate content was increased. 2. The administration of a lipid fraction (TL) or protein fractions (CIF and TP) of thymus extracts to thymectomized rabbits in short-term experiments increased the ATP content o...

Alkaline phosphatase from Escherichia coli catalyzes the hydrolysis of S-substituted monoesters of phosphorothioic acid of the type RSP03Naz (R = -CH2CH2NH2,-CH2CHzNHCOCH3,-CH,COOH, or -CH2CHzCOOCzH~), at the S-P bond, to yield orthophosphate and the corresponding thioalcohols. The rate of enzymic hydrolysis of cysteamine S-phosphate was measured at different pH values and substrate concentrati...

Erythrocyte ghosts have been found to be peculiarly useful for the study of the metabolism of nucleosides (1, 2). Preparations made by osmotic hemolysis were found to be unable to metabolize glucose. Adenosine, however, caused a disappearance of inorganic phosphate from ghost plasma suspensions with an equivalent production of organic acid-soluble ester phosphate. There was a simultaneous disap...

Saygin and Decker [6, 7] have reported that the formation of hydroxamic acids in solutions containing ATP, MgCl2, hydroxylamine and an acidic acceptor (acetic acid or amino acids) is not accompanied by the release of inorganic phosphate from ATP. Using an ion exchange chromatography method developed by Lowenstein [8] to separate the various components of such reaction mixtures, we now show that...

The Na(+), K(+), and inorganic phosphate levels of the plasma and sartorius muscle of the toad Bufo marinus were determined. Soaking in normal Ringer brought about the usual cation shifts, but did not alter the level of inorganic phosphate in the cell. Increases in the external phosphate level brought about an increase in the internal phosphate, but the apparent phosphate space of muscle is som...

Chloroplast phosphofructokinase from spinach (Spinacia oleracea L.) was purified approximately 40-fold by a combination of fractionations with ammonium sulfate and acetone followed by chromatography on DEAE-Sephadex A-50. Positive cooperative kinetics was observed for the interaction between the enzyme and the substrate fructose 6-phosphate. The optimum pH shifted from 7.7 toward 7.0 as the fru...