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Mitochondrial affinity for ADP is twofold lower in creatine kinase knock‐out muscles
Author(s) -
ter Veld Frank,
Jeneson Jeroen A. L.,
Nicolay Klaas
Publication year - 2005
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2004.04529.x
Subject(s) - creatine kinase , mitochondrion , cytosol , creatine , skeletal muscle , gastrocnemius muscle , biology , cardiac muscle , myoglobin , biochemistry , chemistry , medicine , endocrinology , enzyme
Adaptations of the kinetic properties of mitochondria in striated muscle lacking cytosolic (M) and/or mitochondrial (Mi) creatine kinase (CK) isoforms in comparison to wild‐type (WT) were investigated in vitro . Intact mitochondria were isolated from heart and gastrocnemius muscle of WT and single‐ and double CK‐knock‐out mice strains (cytosolic (M‐CK –/– ), mitochondrial (Mi‐CK –/– ) and double knock‐out (MiM‐CK –/– ), respectively). Maximal ADP‐stimulated oxygen consumption flux (State3 V max ; nmol O 2 ·mg mitochondrial protein −1 ·min −1 ) and ADP affinity (; µ m ) were determined by respirometry. State 3 V max and of M‐CK –/– and MiM‐CK –/– gastrocnemius mitochondria were twofold higher than those of WT, but were unchanged for Mi‐CK –/– . For mutant cardiac mitochondria, only the of mitochondria isolated from the MiM‐CK –/– phenotype was different (i.e. twofold higher) than that of WT. The implications of these adaptations for striated muscle function were explored by constructing force‐flow relations of skeletal muscle respiration. It was found that the identified shift in affinity towards higher ADP concentrations in MiM‐CK –/– muscle genotypes may contribute to linear mitochondrial control of the reduced cytosolic ATP free energy potentials in these phenotypes.