Difference between revisions of "Ascorbate"

Latest revision as of 09:20, 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 1: / Line 1: @@
 {{MitoPedia
 |abbr=As
-|description=In respiratory assays for cytochrome c oxidase (COX; [[Complex IV|complex CIV]]) activity, '''ascorbate''' is added as regenerating system for reduced [[TMPD|TMPD]].
+|description=In respiratory assays for cytochrome ''c'' oxidase activity ([[Complex IV|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.
 |info=[[MiPNet06.06]]
 }}
-{{MitoPedia topics
+__TOC__
-|mitopedia topic=Substrate and metabolite
-}}
+== Application in [[HRR]] ==
-== Application in [[HRR]]  ==
+{{Chemical_description
+|abbr=As
+|trivial name=Ascorbate
+|complete name=(+)-Sodium L-ascorbate
+|chem formula=C<sub>6</sub>H<sub>7</sub>NaO<sub>6</sub>
+|molar mass=198.11
+|vendor=Sigma-Aldrich
+|product number=A7631
+|store at=RT
+|sensitivity=
+|cas=134-03-2
+|h statements=
+|h info=
+}}<!--:::: '''As: Ascorbate sodium salt''' (Sodium L-ascorbate); Sigma A 7631, 100 g, store at RT; M = 198.1 g·mol<sup>-1</sup>.-->
+:::: <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> -->
+:::: '''Preparation of 800 mM stock solution''' (dissolved in H<sub>2</sub>O) for '''2-mL O2k-chamber''':
+::::# Weigh 792.4 mg of ascorbate sodium salt and dissolve in 3 mL H<sub>2</sub>O
+::::# 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]]
-'''As: Ascorbate sodium salt''' (Succinate disodium salt, hexahydrate, C<sub>6</sub>H<sub>7</sub>0<sub>6</sub>Na); Sigma A 4034, 100 g, store at R.T.; FW = 198.1
+::::* Titration volume ('''2-mL O2k-chamber'''): 5 µL using a 25 µL Hamilton syringe.
+::::* Final concentration: 2 mM.
-<span style="color:#8B008B"> '''Caution:''' Light sensitive (store solution in a dark glass vial).</span>
-'''Preparation of 800 mM stock solution''' (dissolved in H<sub>2</sub>O):
+:::: '''Preparation of 1000 mM stock solution''' (dissolved in H<sub>2</sub>O) for '''0.5-mL O2k-chamber''':
-::1) weigh 1.584 g of Ascorbate sodium salt and dissolve in 10 ml H<sub>2</sub>O
+::::# Weigh 990.5 mg of ascorbate sodium salt and dissolve in 3 mL H<sub>2</sub>O
-::2) To prevent autooxidation, adjust pH to ca 6 with ascorbic acid (a 137.6 mg ml-1 solution of pH ca 2).
+::::# To prevent autoxidation, adjust pH to approx. 6 with 1 M HCl.
-::3) Divide into 0.2 ml portions.
+::::# Adjust final volume to 5 mL and divide into 0.2 mL portions in dark vials.
-::4) Store frozen at -20 °C.
+::::# Store frozen at -20 °C.
+:::»'''O2k manual titrations:''' [[MiPNet09.12]]
-'''Oxygraph-2k Manual Titrations:''' [[MiPNet09.12]]
+::::* Titration volume ('''0.5-mL O2k-chamber'''): 1 µL using a 10 µL Hamilton syringe.
+::::* Final concentration: 2 mM.
-::* Titration volume: 5 µl using a 25 µl syringe
+{{MitoPedia topics
-::* Final conc. in 2 ml O2k-chamber: 2 mM
+|mitopedia topic=Substrate and metabolite
+}}