Difference between revisions of "Ascorbate"

Revision as of 09:17, 10 June 2021

high-resolution terminology - matching measurements at high-resolution

Ascorbate

Description

In respiratory assays for cytochrome c oxidase activity (Complex IV, CIV), ascorbate is added as regenerating system to maintain TMPD in a reduced state. It has to be titrated into the respiration medium prior to the addition of TMPD, otherwise the autoxidation reaction velocity is permanently elevated.

Abbreviation: As

Reference: MiPNet06.06

Application in HRR

As: Ascorbate ((+)-Sodium L-ascorbate; C₆H₇NaO₆), Sigma-Aldrich: A7631, store at RT, CAS: 134-03-2, M = 198.11 g·mol^-1

Caution: Solutions of ascorbic acid are rapidly oxidized in air and in alkaline media; the compound should be protected from air and light. See 'ascorbid acid' on PubChem

Preparation of 800 mM stock solution (dissolved in H₂O) for 2-mL O2k-chamber:

Weigh 792.4 mg of ascorbate sodium salt and dissolve in 3 mL H₂O
To prevent autoxidation, adjust pH to approx. 6 with 1 M HCl (approx. 85 µL).
Adjust final volume to 5 mL and divide into 0.2 mL portions in dark vials.
Store frozen at -20 °C.

»O2k manual titrations: MiPNet09.12

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

Preparation of 1000 mM stock solution (dissolved in H₂O) for 0.5-mL O2k-chamber:

Weigh 990.5 mg of ascorbate sodium salt and dissolve in 3 mL H₂O
To prevent autoxidation, adjust pH to approx. 6 with 1 M HCl.
Adjust final volume to 5 mL and divide into 0.2 mL portions in dark vials.
Store frozen at -20 °C.

»O2k manual titrations: MiPNet09.12

Titration volume (0.5-mL O2k-chamber): 1 µL using a 10 µL Hamilton syringe.
Final concentration: 2 mM.

MitoPedia topics: Substrate and metabolite

@@ Line 7: / Line 7: @@
 == Application in [[HRR]] ==
+{{Chemical_description
-:::: '''As: Ascorbate sodium salt''' (Sodium L-ascorbate); Sigma A 7631, 100 g, store at RT; M = 198.1 g·mol<sup>-1</sup>.
+|abbr=As
+|trivial name=Ascorbate
-:::: <span style="color:#8B008B"> '''Caution:''' Solutions of ascorbic acid are rapidly oxidized in air and in alkaline media; the compound should be protected from air and light. See 'ascorbid acid' on [https://pubchem.ncbi.nlm.nih.gov/compound/54670067 PubChem]</span>
+|complete name=(+)-Sodium L-ascorbate
-<!--
+|chem formula=C<sub>6</sub>H<sub>7</sub>NaO<sub>6</sub>
-:::: '''Preparation of 800 mM stock solution''' (dissolved in H<sub>2</sub>O):
+|molar mass=198.11
-::::# Weigh 1.584 g of ascorbate sodium salt and dissolve in 10 mL H<sub>2</sub>O
+|vendor=Sigma-Aldrich
-::::# To prevent autoxidation, adjust pH to approx. 6 with ascorbic acid (a 137.6 mg.mL<sup>-1</sup> solution of pH 2).
+|product number=A7631
-::::# Divide into 0.2 mL portions.
+|store at=RT
-::::# Store frozen at -20 °C.
+|sensitivity=
+|cas=134-03-2
-:::» '''O2k manual titrations:''' [[MiPNet09.12]]
+|h statements=
+|h info=
-::::* Titration volume: 5 µL using a 25 µL syringe.
+}}<!--:::: '''As: Ascorbate sodium salt''' (Sodium L-ascorbate); Sigma A 7631, 100 g, store at RT; M = 198.1 g·mol<sup>-1</sup>.
-::::* Final conc. in 2 mL O2k-chamber: 2 mM.
+:::: <span style="color:#8B008B"> '''Caution:''' Solutions of ascorbic acid are rapidly oxidized in air and in alkaline media; the compound should be protected from air and light. See 'ascorbid acid' on [https://pubchem.ncbi.nlm.nih.gov/compound/54670067 PubChem]</span> -->
+:::: Caution: Solutions of ascorbic acid are rapidly oxidized in air and in alkaline media; the compound should be protected from air and light. See 'ascorbid acid' on [https://pubchem.ncbi.nlm.nih.gov/compound/54670067 PubChem]
--->