Perry 2011 Biochem J: Difference between revisions
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|organism=Human, Rat | |organism=Human, Rat | ||
|tissues=Skeletal muscle | |tissues=Skeletal muscle | ||
|preparations=Permeabilized tissue | |preparations=Permeabilized tissue | ||
|enzymes=Complex I, Complex V; ATP Synthase | |enzymes=Complex I, Complex V; ATP Synthase | ||
| | |injuries=Temperature | ||
|topics=ATP; ADP; AMP; PCr | |topics=ATP; ADP; AMP; PCr | ||
|substratestates=CI | |||
|kinetics=Inhibitor; Uncoupler | |||
|instruments=Oxygraph-2k | |||
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Revision as of 09:37, 9 August 2013
Perry CG, Kane DA, Lin CT, Kozy R, Cathey BL, Lark DS, Kane CL, Brophy PM, Gavin TP, Anderson EJ, Neufer PD (2011) Inhibiting myosin-ATPase reveals a dynamic range of mitochondrial respiratory control in skeletal muscle. Biochem J 437: 215-222. |
Perry CG, Kane DA, Lin CT, Kozy R, Cathey BL, Lark DS, Kane CL, Brophy PM, Gavin TP, Anderson EJ, Neufer PD (2011) Biochem J
Abstract: Assessment of mitochondrial ADP-stimulated respiratory kinetics in PmFBs (permeabilized fibre bundles) is increasingly used in clinical diagnostic and basic research settings. However, estimates of the Km for ADP vary considerably (~20-300 ฮผM) and tend to overestimate respiration at rest. Noting that PmFBs spontaneously contract during respiration experiments, we systematically determined the impact of contraction, temperature and oxygenation on ADP-stimulated respiratory kinetics. BLEB (blebbistatin), a myosin II ATPase inhibitor, blocked contraction under all conditions and yielded high Km values for ADP of >~250 and ~80 ฮผM in red and white rat PmFBs respectively. In the absence of BLEB, PmFBs contracted and the Km for ADP decreased ~2-10-fold in a temperature-dependent manner. PmFBs were sensitive to hyperoxia (increased Km) in the absence of BLEB (contracted) at 30 ยฐC but not 37 ยฐC. In PmFBs from humans, contraction elicited high sensitivity to ADP (Km<100 ฮผM), whereas blocking contraction (+BLEB) and including a phosphocreatine/creatine ratio of 2:1 to mimic the resting energetic state yielded a Km for ADP of ~1560 ฮผM, consistent with estimates of in vivo resting respiratory rates of <1% maximum. These results demonstrate that the sensitivity of muscle to ADP varies over a wide range in relation to contractile state and cellular energy charge, providing evidence that enzymatic coupling of energy transfer within skeletal muscle becomes more efficient in the working state. โข Keywords: Bioenergetics, Blebbistatin, Creatine kinase, Myosin-ATPase, N-benzyltoluene sulfonamide, Skeletal muscle contraction
โข O2k-Network Lab: US_NC Greenville_Neufer PD, CA Toronto Perry CG, US_NC_Greenville_Anderson EJ, CA_Antigonish_Kane DA, US NC Greenville East Carolina Univ
Labels:
Stress:Temperature Organism: Human, Rat Tissue;cell: Skeletal muscle Preparation: Permeabilized tissue Enzyme: Complex I, Complex V; ATP Synthase"Complex V; ATP Synthase" is not in the list (Adenine nucleotide translocase, Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, Complex V;ATP synthase, Inner mt-membrane transporter, Marker enzyme, Supercomplex, TCA cycle and matrix dehydrogenases, ...) of allowed values for the "Enzyme" property. Regulation: ATP; ADP; AMP; PCr"ATP; ADP; AMP; PCr" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property.
HRR: Oxygraph-2k