As phosphate derivatives form such important intermediates between the functioning of tissues and the metabolism which supports function, we decided to investigate the levels of certain phosphates in brain slices before and during metabolism in vitro. Investigation of this type appeared all the more necessary because there is now an extremely interesting group of observations on the levels of p...

Earlier studies showed that there is significant creatine kinase activity in the epiphyseal growth cartilage, and there is stage-specific isoform expression. To further explore the role of this enzyme in cartilage development, we disrupted the creatine kinase creatine phosphate (CK-CP) circuit using the creatine analogue, cyclocreatine. We found that while cyclocreatine decreased creatine kinas...

The activation of purified ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) has been studied in the presence of sugar phosphates, and the effect of rubisco activase on this process determined. During an 11-minute time course at pH 7.7 and 11 micromolar CO(2), the activation of rubisco was strongly inhibited by ribulose-1,5-bisphosphate (4 millimolar), fructose-1,6-bisphosphate (1 milli...

The observation that increased muscular activity leads to muscle hypertrophy is well known, but identification of the biochemical and physiological mechanisms by which this occurs remains an important problem. Experiments have been described (5, 6) which suggest that creatine, an end product of contraction, is involved in the control of contractile protein synthesis in differentiating skeletal ...

Recovery of postischemic function may be limited by energy synthesis by mitochondria, energy transfer via the creatine kinase reaction, or energy utilization at myofibrils. To identify the limiting step, we defined the relations among oxygen consumption, creatine kinase reaction velocity and cardiac performance in myocardium reperfused following mild, moderate, and severe ischemia. Isolated iso...

Phosphorus-31 nuclear magnetic resonance (31P NMR) can estimate tissue intracellular pH as well as the content of high-energy phosphate metabolites in isolated perfused hearts. We used 31P NMR to examine mechanisms associated with the recovery of ventricular function in hearts subjected to global ischemia and reperfusion, with special emphasis on intracellular pH, a previously unreported variab...