This invention provides transgenic plants that have increased or decreased activity or uridine 5' -diphospho-galactose 4-epimerase. Controlling the level of uridine 5' -diphospho-galactose 4-epimerase in the transgenic plants is used to regulate the nutritional profile of the plant by controlling the use of glucose and/or galactose. An isolated polynucleotide coding for the potato uridine 5' -diphospho-galactose 4-epimerase protein, its antisense equivalent and the nucleic acid sequence of potato uridine 5' -diphospho-galactose --epimerase are also provided. The present invention also provides a method for reducing the activity or uridine 5' -diphospho-galactose 4-epimerase activity in plants. The present invention also provides a method of producing bulk quantities of uridine 5' -diphospho-galactose 4-epimerase enzyme in transgenic plants.
