Bifunctional coenzyme A synthase is an
enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
that in mammals is encoded by the ''COASY''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
that catalyses the synthesis of
coenzyme A
Coenzyme A (CoA, SHCoA, CoASH) is a coenzyme, notable for its role in the Fatty acid metabolism#Synthesis, synthesis and Fatty acid metabolism#.CE.B2-Oxidation, oxidation of fatty acids, and the oxidation of pyruvic acid, pyruvate in the citric ac ...
from 4'-
phosphopantetheine.
Function
COASY is an enzyme that catalyzes the last two steps in the synthesis of
coenzyme A
Coenzyme A (CoA, SHCoA, CoASH) is a coenzyme, notable for its role in the Fatty acid metabolism#Synthesis, synthesis and Fatty acid metabolism#.CE.B2-Oxidation, oxidation of fatty acids, and the oxidation of pyruvic acid, pyruvate in the citric ac ...
from vitamin B
5 (
pantothenic acid
Pantothenic acid (vitamin B5) is a B vitamin and an essential nutrient. All animals need pantothenic acid in order to synthesize coenzyme A (CoA), which is essential for cellular energy production and for the synthesis and degradation of prote ...
). The primary substrate is 4'-
phosphopantetheine and COASY is a bifunctional enzyme in this pathway:
* 4′-Phosphopantetheine is adenylated to form dephospho-CoA by the enzyme
phosphopantetheine adenylyl-transferase (PPAT; CoaD)
* Next, dephospho-CoA is phosphorylated to coenzyme A by the enzyme
dephospho-CoA kinase (DPCK; CoaE)
In mammals this is a single enzyme, but in organisms including yeast and bacteria these enzymes are encoded by separate genes.
Interactions
COASY has been shown to
interact with
P70-S6 Kinase 1
Ribosomal protein S6 kinase beta-1 (S6K1), also known as p70S6 kinase (p70S6K, p70-S6K), is an enzyme (specifically, a protein kinase) that in humans is encoded by the ''RPS6KB1'' gene. It is a serine/threonine kinase that acts downstream of Phos ...
.
In 2009, COASY has also been implicated in
PI3K signaling, as it was shown to interact with a regulatory subunit of PI3K.
Clinical significance
Loss of function mutations to ''COASY'' have been associated with an ultra-rare disease that causes
neurodegeneration with brain iron accumulation called
COASY protein-associated neurodegeneration (CoPAN), or NBIA6.
References
External links
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Further reading
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