Seppet 2001 Biochim Biophys Acta

Seppet EK, Kaambre T, Sikk P, Tiivel T, Vija H, Tonkonogi M, Sahlin K, Kay L, Appaix F, Braun U, Eimre M, Saks VA (2001) Functional complexes of mitochondria with Ca,Mg ATPases of myofibrils and sarcoplasmic reticulum in muscle cells. Biochim Biophys Acta 1504: 379-395.

» PMID: 11600563

Seppet EK, Kaambre T, Sikk P, Tiivel T, Vija H, Tonkonogi M, Sahlin K, Kay L, Appaix F, Braun U, Eimre M, Saks VA (2001) Biochim. Biophys. Acta

Abstract: Regulation of mitochondrial respiration in situ in the muscle cells was studied by using fully permeabilized muscle fibers and cardiomyocytes. The results show that the kinetics of regulation of mitochondrial respiration in situ by exogenous ADP are very different from the kinetics of its regulation by endogenous ADP. In cardiac and m. soleus fibers apparent Km for exogenous ADP in regulation of respiration was equal to 300–400 μM. However, when ADP production was initiated by intracellular ATPase reactions, the ADP concentration in the medium leveled off at about 40 μM when about 70% of maximal rate of respiration was achieved. Respiration rate maintained by intracellular ATPases was suppressed about 20–30% during exogenous trapping of ADP with excess pyruvate kinase (PK, 20 IU/ml) and phosphoenolpyruvate (PEP, 5 mM). ADP flux via the external PK+PEP system was decreased by half by activation of mitochondrial oxidative phosphorylation. Creatine (20 mM) further activated the respiration in the presence of PK+PEP. It is concluded that in oxidative muscle cells mitochondria behave as if they were incorporated into functional complexes with adjacent ADP producing systems – with the MgATPases in myofibrils and Ca,MgATPases of sarcoplasmic reticulum. • Keywords: Muscle, Respiration, Mitochondrion, ADP, ATPase

• O2k-Network Lab: EE_Tartu_Seppet EK, FR Grenoble Saks VA

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Organism: Human  Tissue;cell: Skeletal Muscle"Skeletal Muscle" is not in the list (Heart, Skeletal muscle, Nervous system, Liver, Kidney, Lung;gill, Islet cell;pancreas;thymus, Endothelial;epithelial;mesothelial cell, Blood cells, Fat, ...) of allowed values for the "Tissue and cell" property.  Preparation: Permeabilized Cells"Permeabilized Cells" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property., Permeabilized Tissue"Permeabilized Tissue" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property. 

HRR: Oxygraph-2k