isocitrate metabolic process

Definition

Target type: biologicalprocess

The chemical reactions and pathways involving isocitrate, the anion of isocitric acid, 1-hydroxy-1,2,3-propanetricarboxylic acid. Isocitrate is an important intermediate in the TCA cycle and the glycoxylate cycle. [ISBN:0198506732]

Isocitrate metabolism is a crucial step in the citric acid cycle (Krebs cycle), a central metabolic pathway that generates energy in the form of ATP through the oxidation of carbohydrates, fats, and proteins. It involves the conversion of isocitrate to α-ketoglutarate, a key intermediate in the cycle. This process is catalyzed by the enzyme isocitrate dehydrogenase (IDH), which exists in two main forms: IDH1 and IDH2. Both enzymes require NAD+ as an electron acceptor and use it to oxidize the secondary alcohol group of isocitrate to a ketone group, yielding α-ketoglutarate. However, they differ in their localization and cofactor requirements. IDH1 is located in the cytoplasm and uses NADP+ as a cofactor, while IDH2 resides in the mitochondria and utilizes NAD+ as a cofactor.

The reaction catalyzed by IDH is a decarboxylation, meaning that it involves the release of carbon dioxide (CO2) from isocitrate. This decarboxylation step is highly regulated and is influenced by factors such as the availability of substrates (isocitrate and NAD+), the presence of inhibitors, and the cellular energy state.

The importance of isocitrate metabolism lies in its role in energy production, but it also contributes to the biosynthesis of various essential molecules, including amino acids, fatty acids, and heme. Additionally, isocitrate metabolism is linked to other metabolic pathways, such as the glyoxylate cycle, which allows organisms to utilize two-carbon compounds like acetate as a carbon source.

In summary, isocitrate metabolism is a vital process that plays a crucial role in cellular energy production and the biosynthesis of essential molecules. It involves the conversion of isocitrate to α-ketoglutarate via the enzyme IDH, with the release of CO2 as a byproduct. This process is tightly regulated and is influenced by several factors, highlighting its importance in maintaining cellular homeostasis.'
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Proteins (2)

Compounds (12)