Pyrophosphate: fructose 6-phosphate phosphotransferase in germinating castor bean seedlings

The distribution of enzymes interconverting fructose 6-phosphate and fructose 1,6-bisphosphate has been studied in a range of tissues from castor bean seedlings. In each tissue the activity of PP i:fructose 6-phosphate phosphotransferase was greater than phosphofructokinase and substantial compared with fructose 1,6-bisphosphatase. PP i:fructose 6-phosphate phosphotransferase in endosperm is apparently confined to the cytoplasm. The role of this latter enzyme in vivo is discussed.