Shikimic acid

Jump to: navigation, search
Shikimic acid
Chemical structure of shikimic acid 3D model of 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.

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).

File:Shikimate pathway 1.png
Biosynthesis of 3-dehydroquinate from phopsphoenolpyruate and erythrose-4-phosphate

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.

File:Shikimate pathway 2.png
Biosynthesis of shikimic acid from 3-dehydroquinate

References

  1. Bradley, David (2005-12). "Star role for bacteria in controlling flu pandemic?" (html). Nature Reviews Drug Discovery. 4: 945–946. Retrieved 2007-03-07. Check date values in: |date= (help)

External links

de:Shikimisäure it:Acido shikimico hu:Sikimisav


Linked-in.jpg