Difference between revisions of "Talk:Glycerophosphate"

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Application in HRR (updated instructions)

Gp: rac-Glycerol 1-phosphate disodium salt hexahydrate sc-215789', store at +4°C; M = 324.13 g·mol^-1

Preparation of 1 M stock solution (1 mL, dissolved in H₂O):

Weigh 324 mg of Gp and dissolve in 845 µL H2O.
Divide into 0.2 mL portions.
Store frozen at -20 °C.

» O2k manual titrations MiPNet09.12 O2k-Titrations

Titration volume (2-mL O2k-chamber): 20 µL using a 50 µL Hamilton syringe.
Titration volume (0.5-mL O2k-chamber): 5 µL using a 25 µL Hamilton syringe.
Final concentration: 10 mM.

If a racemic mixture (like Sigma G-2138) is replaced by the biologically active enantiomer the amount of substance (measured in moles) usually has to be halved. However, also consider that stated purities may vary, requiring further adjustments.

2021-02: The preparation instructions were updated to take the volume of the solute (Gp) into account. The concentrations prepared following the former instructions (see Discussion section) are sufficiently high for SUIT protocol titrations.

pH

pH has been check in Glycerophospate (Gp) stock solution (Sigma G7886), showing a high pH (~9). However, the high pH in the Gp stock does not affect the pH in the chamber when adding 20 µl in MiR05 medium. We measured the pH with the O2k-FluoRespirometer. We observed no significant changes (no more than 0.1, see picture below) in the pH after adding 20 µl of Gp to the MiR05-Kit medium. - Passrugger M 2017-08-31

Glycerophosphate out of stock

Sigma G-2138

Sigma does not sell DL-alpha-glycerophosphate disodium salt hexahydrate (FW = 324.1; Sigma G-2138, CAS# 1555-56-2 (anhydrous)) any more (personal communication with Dr. Zdenek Drahota, Dept. of Bioenergetics, Institute of Physiology, Academy of Sciences of the Czech Rep.)!

In Dr. Drahota's lab a 1 M stock solution is used and the final concentration in the O2k-Chamber is 10 mM.

Alternatives

Racemic disodium salt hexahydrate: CAS#: 3325-00-6, "identical" (not considering purity) to the discontinued Sigma product mentioned above, but actual availability would have to be checked with each individual supplier
- CHEMOS: 151924
- BOC Sciences: 3325-00-6 (sic!, they use CAS numbers as their product numbers, which actually makes a lot of sense).
- Advance Scientific & Chemical: G2218.
Racemic magnesium salt: AppliChem: A4558,1000
Enantiopure lithium salt: Sigma: 94124
Enatiopure bis(cyclohexylammonium) salt: Sigma: G7886

Based on a web search the substance CAS 57-03-4 seems to refer to the free acid, probable in as racemic mixture. However, the confusion about Alpha Glycerol Phosphate is so widespread that even ß-glycerolphosphate (a definitively different compound !!) can be found with the same CAS number on the web...

The compound from Sigma (that was used previously and is no longer available) was the sodium salt of the racemat (CAS# 1555-56-2 (anhydrous), CAS#: 3325-00-6 (hexahydrate, maybe more CAS numbers) see: Glycerophosphate

If my guess in respect to CAS 57-03-4 is correct (free acid, racemic) this would be a reasonable substitution for the racemic sodium form, only with a bit more work to prepare the stock solution. As you can see from the link there are some companies offering the racemic sodium salt, however we have not yet checked if the substance is REALLY available and we have not done any application tests. - Fasching Mario 2014-07-09

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 ::::* 10,000 times (2016-07-14)
 ::::*  5,000 times (2014-11-12)
+== Application in [[HRR]] (updated instructions) ==
+::: '''Gp: rac-Glycerol 1-phosphate disodium salt hexahydrate''' '''sc-215789'''', store at +4°C; '''M = 324.13 g·mol<sup>-1</sup>'''
+:::: '''Preparation of 1 M stock solution''' (1 mL, dissolved in H<sub>2</sub>O):
+::::# Weigh 324 mg of Gp and dissolve in 845 µL H2O.
+::::# Divide into 0.2 mL portions.
+::::# Store frozen at -20 °C.
+:::» '''O2k manual titrations'''  [[MiPNet09.12 O2k-Titrations]]
+::::* Titration volume ('''2-mL O2k-chamber'''): 20 µL using a 50 µL Hamilton syringe.
+::::* Titration volume ('''0.5-mL O2k-chamber'''): 5 µL using a 25 µL Hamilton syringe.
+::::* Final concentration: 10 mM.
+:::: If a racemic mixture (like Sigma G-2138) is replaced by the biologically active enantiomer the amount of substance (measured in moles) usually has to be halved. However, also consider that stated purities may vary, requiring further adjustments.
+:::: 2021-02: The preparation instructions were updated to take the volume of the solute (Gp) into account. The concentrations prepared following the former instructions (see Discussion section) are sufficiently high for SUIT protocol titrations.
 == pH ==