A new method of assessing rates of the futile cycle during glycolytic and gluconeogenic metabolism
A method for assessing rates of the futile cycle is presented, and it is illustrated in vitro. Glycolytic- and gluconeogenic-type cycles are simulated for the reactions catalyzed by phosphofructokinase (EC 220.127.116.11) and fructose-1,6-bisphosphatase (EC 18.104.22.168) in assays systems in which the cycle rates in either direction can be varied and determined. While either system is sustaining a net flux of carbons in a given direction, the flux of radioactively labeled carbons in the opposite direction is determined. Different cycle rates are obtained by varying phosphofructokinase activity while keeping fructose-1,6-bisphosphatase activity constant in the ‘gluconeogenic’ simulation and varying fructose-1,6-bisphosphatase while keeping phosphofructokinase activity constant in the ‘glycolytic’ simulation. A direct, linear relationship was found between the cycle rate and the radioactive labeling of fructose 1,6-bisphosphate from [U-14C]glucose 6-phosphate during net gluconeogenic carbon flux.
Artículo de publicación SCOPUS
Quote ItemArchives of Biochemistry and Biophysics, Volumen 321, Issue 2, 2018, Pages 517-525