Phosphofructokinase in rabbit dental pulp is less sensitive to ATP inhibition

ATP-dependent profiles of phosphofructokinase (PFK) activity were determined in both crude and Sephadex G-25-filtered fractions from rabbit dental pulp. ATP had a dual effect on PFK as an activator and an inhibitor, according to its concentration. Gel-filtered PFK showed a similar profile to that of crude PFK, indicating a lack of low-molecular-weight effector(s) for PFK in rabbit dental pulp. For complete inhibition of the PFK in rabbit dental pulp, 5 mM ATP was required. This level of ATP is much higher than that required for other typical isozymes of PFK from liver, skeletal muscle or brain. It is postulated that differences in the properties of PFK isozymes are due not only to the subunit structure but also to the presence of other effectors.