Open AccessThe effect of inorganic pyrophosphate on the activity and P i ‐binding properties of mitochondrial F 1 ‐ATPase
Author(s) -
KALASHNIKOVA Tatyana Yu.,
MILGROM Yakov M.,
MURATALIEV Marat B.
Publication year - 1988
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1988.tb14364.x-i2
Subject(s) - atp hydrolysis , atpase , pi , pyrophosphate , enzyme , chemistry , hydrolysis , biochemistry , mitochondrion , f atpase , biophysics , biology , thylakoid , chloroplast , gene
Interaction of F 1 ‐ATPase from beef heart mitochondria with PP i has been investigated. The presence of PP i in the ATPase assay medium does not affect the initial rate of ATP hydrolysis by F 1 ‐ATPase, but slows down the decrease of enzyme activity in the course of ATP hydrolysis and increases the steady‐state rate of ATP hydrolysis. Being present in the ATPase assay medium, PP i accelerates the ATP‐dependent reactivation of an inactive complex formed by F 1 ‐ATPase and ADP. This inactive complex is also reactivated after preincubation with PP i . F 1 ‐ATPase, preincubated with PP i , is inactivated by azide much more slowly than is the non‐preincubated enzyme, PP i stimulates the binding of P i to F 1 ‐ATPase by decreasing mainly the K d for P i and only slightly raising the stoichiometry of high‐affinity P i binding. It follows from the results obtained that PP i interacts with the non‐catalytic site(s) of F 1 ‐ATPase.