- high-resolution terminology - matching measurements at high-resolution
Magnesium Green
Description
Magnesium Green(MgG) belongs to the extrinsic fluorophores applied for measurement of mitochondrial ATP production with mitochondrial preparations. This fluorescent dye fluoresces when bound to Mg2+. The technique to measure mitochondrial ATP production is based on the fact that Mg2+ present different dissociation constants for ADP and ATP, and the adenine nucleotide translocase (ANT) exchanges ATP for ADP.
Abbreviation: MgG
Reference: Chinopoulos 2014 Methods Enzymol
MitoPedia methods:
Fluorometry
Magnesium Green in high-resolution respirometry HRR
Instrument
O2k-Fluo LED2-Module) selecting the Fluorescence-Sensor Blue. Use black stoppers with black cover-slips to exclude disturbances by external light sources.
- O2k-FluoRespirometer with Fluorescence-Sensor Blue/Filter Set MgG / CaG
- Magnesium Green and Calcium Green share the same fluorophore moiety in their molecular structure. Therefore, the optical properties are very similar and the same fluorescence sensor and filter set can be used.
- Signal and output:
- Signal: The O2k-Fluo LED2-Module is operated through the amperometric (Amp)-Channel of the O2k, with electric current (ampere [A]) as the primary signal.
- Output: The focus of the output with Magnesium Green is on Type B: Flow, flux, rate.
The fluorescent dye
Magnesium GreenTM is a registered trademark and available from Thermo Fisher Scientific (former: Invitrogen) in several formulations. For measuring mitochondrial ATP production a membrane impermeant formulation must be chosen (e.g. #M3733). Note that while its KD for magnesium is 1.0 mM, its KD for calcium is 6 µM: Magnesium Green binds stronger to calcium than to magnesium and cannot be used in the presence of significant concentrations of free calcium. Possible contaminations with transition metals should be complexed by a small (µM range) concentration of EDTA or DTPA.
Preparation of MgG solution
Experimental media for the MgG assay
Kd determination of ADP or ATP to Mg2+ using MgG
To assess the exchange of ADP/ATP by ANT using MgG, the Kd of ADP and ATP to Mg2+ should be previously calculated for the pertaining experimental conditions.
