- high-resolution terminology - matching measurements at high-resolution
Malate
Description
Malate and glutamate are anions which cannot permeate through the lipid bilayer of membranes and hence require carriers, which is also true for pyruvate. Malate alone cannot support respiration of mt-preparations as mitochondrial respiration depends on a continuous flow of substrates across the mitochondrial membranes into the matrix space. Malate dehydrogenase located in the mitochondrial matrix oxidizes malate to oxaloacetate.
Abbreviation: M
Reference: Gnaiger 2012 MitoPathways, MiPNet09.12
MitoPedia topics: Substrate and metabolite
Application in HRR
M: Malate (L-Malic acid, C4H605); Sigma M 1000, 100 g, store at R.T.; FW = 134.1
Preparation of 400 mM stock solution (dissolved in H2O):
- 1) Weigh 268.2 mg of L-Malic acid.
- 2) Add 3 ml H2O.
- 3) Neutralize with 10 N KOH (approx. 350 µl).
- 4) Adjust final volume to 5 ml (in 5 ml volumetric glass flask).
- 5) Divide into 0.5 ml portions.
- 6) Store frozen at -20 °C.
Comment: 800 mM stock until 2013-11-20.
Oxygraph-2k manual titrations: MiPNet09.12 O2k-Titrations
- Titration volume: 2.5 µl using a 10 µl Hamilton syringe.
- Final conc. in 2 ml O2k-chamber: 0.5 mM.
Malate: 0.5 mM versus 2 mM in HRR
In mitochondrial preparations obtained from a diversity of tissues and organisms malate at concentrations >0.5 mM exerted an inhibitory effect on CII linked and CI+II linked respiration, whereas 0.5 mM malate was saturating for CI linked respiration. Therefore, we recommend to use malate at a concentration of 0.5 mM in SUIT protocols.
- >> Further details: Discussion.
