Phosphopantetheine, also known as 4'-phosphopantetheine, is a prosthetic group of several acyl carrier proteins including the acyl carrier proteins (ACP) of

fatty acid synthase Fatty acid synthase (FAS) is an enzyme that in humans is encoded by the ''FASN'' gene. Fatty acid synthase is a multi-enzyme protein that catalyzes fatty acid synthesis. It is not a single enzyme but a whole enzymatic system composed of two iden ...

s, ACPs of

polyketide synthase Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). First studied in the early 20th century, discovery, biosynth ...

s, the peptidyl carrier proteins (PCP), as well as aryl carrier proteins (ArCP) of

nonribosomal peptide synthetases Nonribosomal peptides (NRP) are a class of peptide secondary metabolites, usually produced by microorganisms like bacteria and fungi. Nonribosomal peptides are also found in higher organisms, such as nudibranchs, but are thought to be made by bacter ...

(NRPS). It is also present in formyltetrahydrofolate dehydrogenase. Subsequent to the expression of the ''apo''

acyl carrier protein The acyl carrier protein (ACP) is a cofactor of both fatty acid and polyketide Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene ...

, 4'-phosphopantetheine moiety is attached to a serine residue. The coupling involves formation of a

phosphodiester In chemistry, a phosphodiester bond occurs when exactly two of the hydroxyl groups () in phosphoric acid react with hydroxyl groups on other molecules to form two ester bonds. The "bond" involves this linkage . Discussion of phosphodiesters is d ...

linkage. This coupling is mediated by

acyl carrier protein synthase In enzymology and molecular biology, a holo- cyl-carrier-proteinsynthase (ACPS, ) is an enzyme that catalyzes the chemical reaction: :CoA- '-phosphopantetheine+ apo-acyl carrier protein \rightleftharpoons adenosine 3',5'-bisphosphate + holo-acy ...

(ACPS), a

4'-phosphopantetheinyl transferase In enzymology and molecular biology, a holo- cyl-carrier-proteinsynthase (ACPS, ) is an enzyme that catalyzes the chemical reaction: :CoA- '-phosphopantetheine+ apo-acyl carrier protein \rightleftharpoons adenosine 3',5'-bisphosphate + holo-acy ...

. Phosphopantetheine prosthetic group covalently links to the acyl group via a high energy thioester bond. The flexibility and length of the phosphopantetheine chain (approximately 2 nm) allows the covalently tethered intermediates to access spatially distinct enzyme-active sites. This accessibility increases the effective molarity of the intermediate and allows an assembly line-like process.

References

Biomolecules Metabolism Thiols {{Metabolism-stub

See also

References