Difference between revisions of "Ascorbate"

Revision as of 11:15, 22 March 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 salt (Sodium L-ascorbate); Sigma A 7631, 100 g, store at RT; M = 198.1 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 g 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 g 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=Ascorbate sodium salt, C6H7O6Na
+|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.
-| ₀₁₂₃₄₅₆₇₈₉
+|info=[[MiPNet06.06]]
-|info=[[MiPNet03.02]]
+}}
-|type=Enzyme
+__TOC__
+== Application in [[HRR]] ==
+:::: '''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):
+::::# Weigh 1.584 g of ascorbate sodium salt and dissolve in 10 mL H<sub>2</sub>O
+::::# To prevent autoxidation, adjust pH to approx. 6 with ascorbic acid (a 137.6 mg.mL<sup>-1</sup> solution of pH 2).
+::::# Divide into 0.2 mL portions.
+::::# Store frozen at -20 °C.
+:::» '''O2k manual titrations:''' [[MiPNet09.12]]
+::::* Titration volume: 5 µL using a 25 µL syringe.
+::::* Final conc. in 2 mL O2k-chamber: 2 mM.
+-->
+:::: '''Preparation of 800 mM stock solution''' (dissolved in H<sub>2</sub>O) for '''2-mL O2k-chamber''':
+::::# Weigh 792.4 g 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]]
+::::* 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 H<sub>2</sub>O) for '''0.5-mL O2k-chamber''':
+::::# Weigh 990.5 g 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.
+::::# 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
+|mitopedia topic=Substrate and metabolite
 }}
-{{Labeling}}