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Shikimic acid



Shikimic acid
Chemical name (3R,4S,5R)-3,4,5-Trihydroxy-
1-cyclohexenecarboxylic acid
Chemical formula C7H10O5
Molecular mass 174.15 g/mol
Melting point 185–187 °C
CAS number [138-59-0]
InChI InChI=1/C7H10O5/c8-4-
1-3(7(11)12)2-5(9)6(4)
10/h1,4-6,8-10H,2H2,
(H,11,12)/t4-,5-,6-
/m1/s1/f/h11H
EINECS number 205-334-2
Disclaimer and references

Shikimic acid, more commonly known as its anionic form shikimate, is an important biochemical intermediate in plants and microorganisms. Its name comes from the Japanese flower shikimi (シキミ, Illicium anisatum), from which it was first isolated.

Additional recommended knowledge

Shikimic acid is a precursor for:

In the pharmaceutical industry, shikimic acid from the Chinese star anise is used as a base material for production of Tamiflu (oseltamivir). Although shikimic acid is present in most autotrophic organisms, it is a biosynthetic intermediate and generally found in very low concentrations. The low isolation yield of shikimic acid from the Chinese star anise is blamed for the 2005 shortage of oseltamivir. Shikimic acid can also be extracted from the seeds of the sweetgum fruit, which is abundant in North America, in yields of around 1.5%, so just 4 kg of sweetgum seeds are enough for fourteen packages of Tamiflu. By comparison star anise has been reported to yield 3 to 7% shikimic acid. Recently biosynthetic pathways in E. coli have been enhanced to allow the organism to accumulate enough material to be used commercially.[1]

Biosynthesis

Phosphoenolpyruvate and erythrose-4-phosphate react to form 3-deoxy-D-arabinoheptulosonate-7-phosphate (DAHP), in a reaction catalysed by the enzyme DAHP synthase. DAHP is then transformed to 3-dehydroquinate(DHQ), in a reaction catalysed by DHQ synthase. Although this reaction requires NAD as a cofactor, the enzymic mechanism regenerates it, resulting in the net use of no NAD (note diagram is incorrect).

 

DHQ is dehydrated to 3-dehydroshikimate by the enzyme dehydroquinase, which is reduced by to shikimic acid by the enzyme shikimate dehydrogenase, which uses NADPH as a cofactor.

 

References

  1. ^ Bradley, David (2005-12). "Star role for bacteria in controlling flu pandemic?" (html). Nature Reviews Drug Discovery 4: 945-946. Retrieved on 2007-03-07.
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Shikimic_acid". A list of authors is available in Wikipedia.
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