www.checkbiotech.org ; www.raupp.info ; www.czu.cz

Researchers have identified an enzyme in grapes that helps convert vitamin C
into tartaric acid, which could have implications for enriching vitamin C in
the world?s most important fruit crop, March 2006.

Tartaric acid is a principal component of grapes, contributing to their
tartness, acidity, taste, and aging potential as wine. Unlike other fruit
acids, tartaric acid is synthesized from vitamin C instead of sugars.

While the intermediates in the production chain are known, none of the
enzymes responsible for synthesis have been identified. By examining the
changing expression levels of both genes and metabolites in developing
berries of the cultivated grape Vitis vinifera, Christopher Ford and
colleagues identified several potential candidate enzymes. They compared the
acid content of 28 related grape species and found one, Ampelopsis
aconitifolia, which had no tartaric acid.

This particular grape lacked one of the candidate enzymes that catalyzes a
key intermediate step of vitamin C conversion.

Consequently, A. aconitifolia berries were found to accumulate about 3 times
the vitamin C as other grape species. The authors believe manipulating this
enzyme in cultivated grapes could lead to the production of grapes rich in
vitamin C.

Article #10864: "L-Tartaric acid synthesis from vitamin C in higher plants"
by Seth DeBolt, Douglas R. Cook, and Christopher M. Ford.

[www.checkbiotech.org]

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