MiPNet12.01 Suppl T-issue
 |
» 
»Versions
Oroboros (2018-11-18) Mitochondr Physiol Network
Abstract: Oroboros (2018) MitoPathways at the Q-junction: mouse skeletal muscle fibers. Mitochondr Physiol Network 12.01(03): Suppl T-issue. » Versions
- Open the pdf document above.
- » Current O2k-series: NextGen-O2k Series XB and O2k Series J
- » Current software versions DatLab 8.0: MitoPedia: DatLab
- Further details: » MitoPedia: O2k-Open Support
• O2k-Network Lab: AT_Innsbruck_Oroboros
Labels: MiParea: Respiration
Organism: Mouse
Tissue;cell: Skeletal muscle
Preparation: Permeabilized tissue
Coupling state: LEAK, ROUTINE, ET
Pathway: N, S, NS, ROX
HRR: Oxygraph-2k, O2k-Protocol
MitoPathways, O2k-Demo, O2k-Core
Limitations of the SUIT protocol
Maximum OXPHOS and ET-capacity
- Evaluation of maximum respiratory capacities requires titration of further substrates activating additional respiratory complexes at the Q-junction (CETF and CGpDH<).
Malate concentration
- The malate concentration was 2 mM, to saturate N-linked respiration. However, at 2 mM malate, the fumarate concentration is increased to a level which inhibits succinate dehydrogenase. Then NS- and S-linked respiratory capacities are underestimated. A malate concentration of 0.5 mM, which saturates N-linked respiration and inhibits S-linked respiration to a lesser extent, represents and improved standard.
- » Optimum malate concentration in SUIT protocols
ROX correction
- The fact that ROX was higher in the NS-substrate state compared to N-linked LEAK respiration indicates that ROX is partially controlled by the substrate state. Therefore, a single measurement of ROX cannot be applied for correction of total oxygen consumption in the different substrate states. Total respiration, therefore, represents apparent coupling states L´, P´ and E´ (Fig. 1). ROX correction is possible in the present experiment only for NS- and S-linked respiration. Azide inhibits not only CIV but other heme-based oxidases and peroxidases, and therefore may interfere with ROX beyond blocking respiratory electron transfer. Based on this argument, a combination of CII- and CIII-inhibitors (malonic acid, antimycin A, myxothiazol) may yield more consistent results, although any ROS scavenged by cytochrome c may in the absence of a CIV-inhibitor result in respiratory oxygen consumption through CIV.
