Open AccessDynamic Properties of a Phosphofructokinase/Pyruvate Kinase System
Author(s) -
CUMME Gerhard A.,
BUBLITZ Renate,
HORN Anton
Publication year - 1981
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1981.tb06197.x
Subject(s) - phosphofructokinase , pyruvate kinase , steady state (chemistry) , glycolysis , biochemistry , pkm2 , enzyme , substrate (aquarium) , pyruvate dehydrogenase phosphatase , pyruvate dehydrogenase kinase , chemistry , biophysics , pyruvate dehydrogenase complex , biology , ecology
It is known from theoretical, work that very simple enzyme systems may, exhibit non‐linear dynamic properties like those found in vivo . To realize such a system experimentally, an ATP‐producing reaction (pyruvate kinase) was coupled with an ATP‐consuming reaction (phosphofructokinase). The substrate‐stat technique has been adapted to characterize each single enzyme as well as to follow up one enzyme in the coupled system. If the plots of both pyruvate kinase activity versus [ADP] and phosphofructokinase activity versus [ATP] are hyperbolic, the coupled system approaches a unique steady state as predicted from the single characteristics. Under assay conditions where phosphofurctokinase is inhibited by ATP, its characteristics as found in a single assay and in the coupled system are different. For a system with ATP‐inhibited phosphofructokinase, a paradoxical behaviour is predicted and is demonstrated experimentally. If the total pyruvate kinase activity is increased over a certain limit, the system is switched from a low [ATP], high‐activity steady state into a high [ATP] low‐activity steady state.