Preferred Label : Acetyl Group Shuttle Pathway;
NCIt related terms : Shuttle for transfer of acetyl groups from mitochondria to the cytosol;
Alternative definition : BIOCARTA: Acetyl-CoA is produced in mitochondria through the metabolism of fatty acids
and the oxidation of pyruvate to acetyl-CoA. When ATP is needed, this acetyl-CoA can
enter the Krebs cycle to drive oxidative phosphorylation. When ATP supplies are abundant,
the acetyl-CoA can be diverted to other purposes like energy storage in the form of
fatty acids. The biosynthesis of fatty acids from this acetyl-CoA cannot take place
directly however, since it is produced inside mitochondria while fatty acid biosynthesis
occurs in the cytosol. Also, there is not a mechanism that directly transports acetyl-CoA
out of mitochondria. To be transported, the acetyl-CoA must be chemically converted
to citric acid using a pathway called the tricarboxylate transport system. Inside
mitochondria, the enzyme citrate synthase joins acetyl-CoA with oxaloacetate to make
citrate. This citrate is transported from the mitochondria to the cytosol, thus transporting
the acetyl-CoA in the form of citrate. Once in the cytosol, the citrate is converted
back to oxaloacetate, which is then reduced to malate. Malate can be oxidized to pyruvate
by the malic enzyme, with production of NADPH as well, that can contribute to fatty
acid biosynthesis. Pyruvate can be reimported back into the mitochondria. Alternatively,
malate can be transported itself back into the mitochondria and used to produce NADH
once inside mitochondria. (This definition may be outdated - see the DesignNote.);
NCIt note : The BIOCARTA Definition (ALT_DEFINITION) for this pathway concept was provided by
BioCarta. This property was not created by, nor is it maintained by the NCI Thesaurus
staff. Additionally, BioCarta is no longer updating its pathway data; thus, the BIOCARTA
Definition might be outdated or inaccurate. Please see the Terms and Conditions for
Use at http://www.biocarta.com/.;
Biocarta ID : h_malatexPathway;
Origin ID : C39144;
UMLS CUI : C1510758;
Semantic type(s)
- has_gene_product_element
- pathway_has_gene_element
