The integration of glycolytic and respiratory machinery

diphosphopyridine nucleotide and its reduced form; glucose-1-P, glucose-i-phosphate; P@,orthophosphate; ATP, adenosine tn phosphate; ADP, adenosine diphosphate; AMP, adenosine mono phosphate; TPN, triphosphopynidine nucleotide; P-eno!pynuvate, phosphorylenolpyruvate. Received for publication December 14, 1964. and pyridine nucleotides and inorganic phosphate play a role in these processes (10—14, 18,19,28—31,34,39,40). 5ev eral investigators, notably Racker (20, 21), Chance (11—14), Aisenberg and Potter (2, 3), and McKee (26) and their associates, have provided models for metabolic con trol by way of these substances. Recently Sols et al. (33) have suggested a “two feed-back mechanism working in series― as a metabolic control point with inhibition of phosphofructokinase by excess ATP. The most direct means of testing such hypotheses would be to study the effects of changes in concentration of these substances on respiration and glycolysis. The difficulty of working with