Phloroglucinol synthase is an

acetyltransferase An acetyltransferase (also referred to as a transacetylase) is any of a class of transferase enzymes that transfers an acetyl group in a reaction called acetylation. In biological organisms, post-translational modification of a protein via acetyl ...

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 ...

involved in the synthesis of

phloroglucinol Phloroglucinol is an organic compound with the formula C6H3(OH)3. It is a colorless solid. It is used in the organic synthesis, synthesis of pharmaceuticals and explosives. Phloroglucinol is one of three isomeric benzenetriols. The other two isom ...

(also known as ''1,3,5-trihydroxybenzene'' or ''cyclohexane-1,3,5-trione''), a pharmaceutically and industrially important benzentriol molecule used in medicines and explosives. The enzyme, as taken from the bacterium

pseudomonas protegens ''Pseudomonas protegens'' are widespread Gram-negative, plant-protecting bacteria. Some of the strains of this novel bacterial species (CHA0 and Pf-5, for example) previously belonged to '' P. fluorescens''. They were reclassified since they see ...

(Pf-5), is a type III

polyketide In organic chemistry, polyketides are a class of natural products derived from a Precursor (chemistry), precursor molecule consisting of a Polymer backbone, chain of alternating ketone (, or Carbonyl reduction, its reduced forms) and Methylene gro ...

synthase In biochemistry, a synthase is an enzyme that catalyses a synthesis process. Note that, originally, biochemical nomenclature distinguished synthetases and synthases. Under the original definition, synthases do not use energy from nucleoside trip ...

. The enzyme cyclizes the activated form of 3,5-dioxoheptanedioate. Phloroglucinol synthase exhibits broad

substrate specificity Chemical specificity is the ability of binding site of a macromolecule (such as a protein) to bind specific ligands. The fewer ligands a protein can bind, the greater its specificity. Specificity describes the strength of binding between a given ...

, able to accept C4-C12

aliphatic In organic chemistry, hydrocarbons ( compounds composed solely of carbon and hydrogen) are divided into two classes: aromatic compounds and aliphatic compounds (; G. ''aleiphar'', fat, oil). Aliphatic compounds can be saturated (in which all ...

acyl-CoAs and phenylacetyl-CoAs, yielding polyoxoalkylated alpha-pyrones by condensation with

malonyl-CoA Malonyl-CoA is a coenzyme A derivative of malonic acid. Biosynthesis Malonyl-CoA cannot cross membranes and there is no known malonyl-CoA import mechanism. The biosynthesis therefore takes place locally: * cytosol: Malonyl-CoA is formed by c ...

. The enzyme catalyzes the following reaction, :3

+ 3 H⁺ =

Phloroglucinol Phloroglucinol is an organic compound with the formula C6H3(OH)3. It is a colorless solid. It is used in the organic synthesis, synthesis of pharmaceuticals and explosives. Phloroglucinol is one of three isomeric benzenetriols. The other two isom ...

+ 3 CO₂ + 3 CoA It was shown that the ''k''_cat for this enzyme (with malony-CoA as a substrate) was 10 min^-1. Its product, phloroglucinol is used in industry as well as in the synthesis of pharmaceuticals. It can be used to make phloroglucinol but it shows low productivity.

References

{{reflist Transferases Enzymes