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.