As a step in the biosynthesis of sinapine the UDP-glucose:sinapate glucosyltransferase catalyses the conversion of sinapic acid to sinapoyl glucose.

A number of plant components including sinapic acid esters restrict the use of oilseed rape products in human and animal nutrition.

In oilseed rape these compounds are present in much higher concentrations than in other oil-rich seeds, which accounts for the bitter taste and astringency of oilseed rape products. The phenolic compounds present in oilseed rape can form complexes with the oilseed rape protein, thus reducing the high nutritional value of the protein. Moreover, these phenolic compounds give rise to an undesirable dark colouration of oilseed rape protein products. Sinapic acid esters, which mainly consist of the bitter substance sinapine (or sinapoyl-choline), normally make up 1-2% of rapeseed meal. Sinapine is the most frequently occurring phenolic acid ester compound, accounting for approximately 80% of the total phenolic content. 

Suppression of the UDP-glucose:sinapate glucosyltransferase leads to a reduction of sinapine content in the seeds of the GM oilseed rape plants.