Aroma biosynthesis in strawberry: S-adenosylmethionine : furaneol O-methyltransferase activity in ripening fruits
| Autor: | Noa Lavid, Margery Koch-Dean, Olga Larkov, Einat Bar, Wilfried Schwab, Uzi Ravid, Efraim Lewinsohn, Ebru Kafkas |
|---|---|
| Přispěvatelé: | Çukurova Üniversitesi |
| Jazyk: | angličtina |
| Rok vydání: | 2002 |
| Předmět: |
Methylation
Gas Chromatography-Mass Spectrometry Substrate Specificity O-methyltransferase activity chemistry.chemical_compound Biosynthesis 2 5-dimethyl-4-hydroxy-3(2H)-furanone (furaneol) methoxyfuraneol Caffeic acid strawberry (Fragaria x ananassa) Food science Furans Rosaceae Aroma O-methyltransferase biology Chemistry food and beverages Ripening Methyltransferases General Chemistry Hydrogen-Ion Concentration biology.organism_classification Furaneol Molecular Weight Biochemistry Fruit Odorants Protocatechuic aldehyde Chromatography Thin Layer General Agricultural and Biological Sciences Coniferyl alcohol |
| ISSN: | 0001-7655 |
| Popis: | WOS: 000176550500023 PubMed ID: 12083877 Among the most important volatile compounds in the aroma of strawberries are 2,5-dimethyl-4-hydroxy3(2H)-furanone (Furaneol) and its methoxy derivative (methoxyfuraneol, mesifuran). Three strawberry varieties, Malach, Tamar, and Yael, were assessed for total volatiles, Furaneol, and methoxyfuraneol. The content of these compounds sharply increased during fruit ripening, with maximum values at the ripe stage. An enzymatic activity that transfers a methyl group from S-adenosylmethionine (SAM) to Furaneol sharply increases during ripening of strawberry fruits. The in vitro generated methoxyfuraneol was identified by radio-TLC and GC-MS. The partially purified enzyme had a native molecular mass of similar to80 kDa, with optimum activity at pH 8.5 and 37 degreesC. A high apparent K-m of 5 mM was calculated for Furaneol, whereas this enzyme preparation apparently accepted as substrates other o-dihydroxyphenol derivatives (such as catechol, caffeic acid, and protocatechuic aldehyde) with much higher affinities (K-m similar to 105, 130, and 20 muM, respectively). A K-m for SAM was found to be similar to5 muM, regardless of the acceptor used. Substrates that contained a phenolic group with only one OH group, such as p-coumaric and trans-ferulic acid, as well as trans-anol and coniferyl alcohol, were apparently not accepted by this activity. It is suggested that Furaneol methylation is mediated by an O-methyltransferase activity and that this activity increases during fruit ripening. |
| Databáze: | OpenAIRE |
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