Lipoic Acid Flashcards
Know Structures!!!!!
- a-Lipoic Acid - Oxidized
- Dihydrolipoic Acid - Reduced
Lipoic acid contains a stereogenic carbon, which then makes it possible to have how many enantiomeric isomers?
- 2
Naturally occuring Lipoic acid is in which configuration?Because biological systems utilize only this form…
- D-lipoic acid
Lipoic acid occurs naturally in the human diet and is found in abundance in animal tissues with high metabolic activity such as what?
Liver, heart, kidney
What types of enzymes cleave lipoic acid from the mitochondrial enzyme complexes that are derived from food?
- Digestive proteolytic enzymes
Where is lipoic acid readily absorbed and converted in the body, and in which form?
- Converted and absorbed in many tissues
- Reduced form, Dihydrolipoic acid
What happens when L-Lipoic acid is taken orally?
- L-Lipoic acid can COMPETITIVELY INHIBIT and ANTAGONIZE the uptake of D-Lipoic acid, these should be avoided!
Where is lipoic acid synthesized in humans?
Liver
Lipoic acid denovo sythesis is driven by what enzyme?
Lipoic acid synthase
Lipoic acid synthase uses what 2 things?
- Medium chain fatty acid - OCTANOIC ACID
2. Amino acid - CYSTEINE
Lipoic acid is first converted to what?
Lipoamide
Which enzyme is responsible for the conversion of Lipoic acid to lipoamide?
Dihydrolipoyl transacetylase [complex 2 of pyruvate dehydrogenase complex]
In what 3 other multienzyme complexes can the enzyme dihydrolipoyl transacetylase (E2) be found in?
- Pyruvate dehydrogenase
* 2. a-ketoglutarate dehydrogenase* - Branched chain a-ketoacid dehydrogenase
What happens when someone ingests an arsenic compound?
Arsenic compounds have the ability to bind to lipoamide [lactic acidosis if pyruvate has nowhere to go, if the PDH complex has no where to run, then build up of lactic acid will ensue]
Which form of Lipoic acid scavenges hydroxyl radicals?
Dihydrolipoic acid (D-lipoic acid)
