Sinapaldehyde is an organic compound that is an intermediate in the formation of lignin. In Arabidopsis thaliana, this compound is part of the lignin biosynthesis pathway. The enzyme dihydroflavonol 4-reductase uses sinapaldehyde and NADPH to produce sinapyl alcohol and NADP+. It is found in Senra incana (Hibisceae). It is a low molecular weight phenol that is susceptible to be extracted from cork stoppers into wine. The reduced epidermal fluorescence1 (ref1) mutant of Arabidopsis thaliana accumulates only 10 to 30% of the sinapate esters found in wild-type plants. Positional cloning of the REF1 gene revealed that it encodes an aldehyde dehydrogenase, a member of a large class of NADP(+)-dependent enzymes that catalyze the oxidation of aldehydes to their corresponding carboxylic acids. Consistent with this finding, extracts of ref1 leaves exhibit low sinapaldehyde dehydrogenase activity.
-P173.gif)