Functional complexes of mitochondria with MgATPase of myofibrils and sarcoplasmic reticulum in muscle cells

Document identifier: oai:dalea.du.se:2322
Keyword: Muscle; Respiration; Mitochondrion; ADP; ATPase
Publication year: 2001
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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.

Authors

E. K. Seppet

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T. Kaambre

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P. Sikk

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T. Tiivel

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H. Vija

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L. Kay

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F. Appaix

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Michail Tonkonogi

Högskolan Dalarna; Medicinsk vetenskap
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Kent Sahlin

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U. Braun

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M. Eimre

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V.A. Saks

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    header: 
        identifier: oai:dalea.du.se:2322
        datestamp: 2021-04-15T12:57:27Z
        setSpec: SwePub-du
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                version: 3.7
            recordInfo: 
                recordContentSource: du
                recordCreationDate: 2006-10-02
            identifier: http://urn.kb.se/resolve?urn=urn:nbn:se:du-2322
            titleInfo: 
                @attributes: 
                    lang: eng
                title: Functional complexes of mitochondria with MgATPase of myofibrils and sarcoplasmic reticulum in muscle cells
            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 CaMgATPases of sarcoplasmic reticulum.

            subject: 
                @attributes: 
                    lang: eng
                topic: Muscle; Respiration; Mitochondrion; ADP; ATPase
            language: 
                languageTerm: eng
            genre: 
                publication/journal-article
                ref
            note: 
                Published
                12
            name: 
                    @attributes: 
                        type: personal
                    namePart: 
                        Seppet
                        E. K.
                    role: 
                        roleTerm: aut
                    @attributes: 
                        type: personal
                    namePart: 
                        Kaambre
                        T.
                    role: 
                        roleTerm: aut
                    @attributes: 
                        type: personal
                    namePart: 
                        Sikk
                        P.
                    role: 
                        roleTerm: aut
                    @attributes: 
                        type: personal
                    namePart: 
                        Tiivel
                        T.
                    role: 
                        roleTerm: aut
                    @attributes: 
                        type: personal
                    namePart: 
                        Vija
                        H.
                    role: 
                        roleTerm: aut
                    @attributes: 
                        type: personal
                    namePart: 
                        Kay
                        L.
                    role: 
                        roleTerm: aut
                    @attributes: 
                        type: personal
                    namePart: 
                        Appaix
                        F.
                    role: 
                        roleTerm: aut
                    @attributes: 
                        type: personal
                        authority: du
                    namePart: 
                        Tonkonogi
                        Michail
                    role: 
                        roleTerm: aut
                    affiliation: 
                        Högskolan Dalarna
                        Medicinsk vetenskap
                    nameIdentifier: 
                        mtn
                        0000-0003-1619-9758
                    @attributes: 
                        type: personal
                    namePart: 
                        Sahlin
                        Kent
                    role: 
                        roleTerm: aut
                    @attributes: 
                        type: personal
                    namePart: 
                        Braun
                        U.
                    role: 
                        roleTerm: aut
                    @attributes: 
                        type: personal
                    namePart: 
                        Eimre
                        M.
                    role: 
                        roleTerm: aut
                    @attributes: 
                        type: personal
                    namePart: 
                        Saks
                        V.A.
                    role: 
                        roleTerm: aut
            originInfo: 
                dateIssued: 2001
                publisher: Elsevier
                place: 
                    placeTerm: Amsterdam
            relatedItem: 
                @attributes: 
                    type: host
                titleInfo: 
                    title: Biochimica et Biophysica Acta - Bioenergetics
                identifier: 
                    0005-2728
                    1879-2650
                part: 
                    detail: 
                            @attributes: 
                                type: volume
                            number: 1504
                            @attributes: 
                                type: issue
                            number: 2-3
                    extent: 
                        start: 379
                        end: 395
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