3-Dehydroquinic acid (DHQ) is the first carbocyclic intermediate of the shikimate pathway. It is created from 3-deoxyarabinoheptulosonate 7-phosphate, a 7-carbon ulonic acid, by the enzyme

DHQ synthase DHQ may refer to: * 3-Dehydroquinic acid, the first carbocyclic intermediate of the shikimate pathway * Digital Humanities Quarterly ''Digital Humanities Quarterly'' is a peer-reviewed open-access academic journal covering all aspects of digital m ...

. The mechanism of

ring closure A cyclic compound (or ring compound) is a term for a compound in the field of chemistry in which one or more series of atoms in the compound is connected to form a ring. Rings may vary in size from three to many atoms, and include examples where al ...

is complex, but involves an aldol condensation at C-2 and C-7. It has the same structure as

quinic acid Quinic acid is a cyclitol, a cyclic polyol, and a cyclohexanecarboxylic acid. It is a colorless solid that can be extracted from plant sources. Quinic acid is implicated in the perceived acidity of coffee. Occurrence and preparation The compound ...

, which is found in coffee, but the C-3 hydroxyl is oxidized to a

ketone In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bo ...

group. 3-Dehydroquinic acid undergoes five further enzymatic steps in the remainder of the shikimate pathway to chorismic acid, a precursor to tyrosine, 3-

phenylalanine Phenylalanine (symbol Phe or F) is an essential α-amino acid with the formula . It can be viewed as a benzyl group substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of alanine. This essential amino a ...

, tryptophan, and some vitamins, including: * Vitamin K * Pteroylmonoglutamic acid, called folate. 3-Dehydroquinate can also be a precursor to pyrroloquinoline quinone (PQQ), an alternate redox coenzyme involved in

oxidative phosphorylation Oxidative phosphorylation (UK , US ) or electron transport-linked phosphorylation or terminal oxidation is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing chemical energy in order to produce adenosine tri ...

Biosynthesis

3-Dehydroquinate goes through beta oxidation, similar to fatty acids. Then, this compound (6-oxo-3-dehydro-quinate) is transaminated to 6-amino-3-dehydroquinate. Then 6-amino-3-dehydro-quinate is dehydrated and reduced to 6-amino-4-desoxy-3-keto-quinate, which reacts with dehydroalanine and alpha-ketoglutarate, to form hexahydro-pyrroloquinoline quinone. This compound is oxidized by

FAD A fad or trend is any form of collective behavior that develops within a culture, a generation or social group in which a group of people enthusiastically follow an impulse for a short period. Fads are objects or behaviors that achieve short- ...

to PQQ.

References

{{DEFAULTSORT:Dehydroquinic acid, 3- Alpha hydroxy acids Ketones Cyclohexanols Triols