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Updated: Aug 17, 2026
Direct Detection of the Acetate-forming Activity of the Enzyme Acetate Kinase
Published on: December 19, 2011
Use of fructose-2,6-diphosphate to assay for phosphofructokinase activity in human muscle
1Department of Pathology, New York Medical College, Valhalla, NY 10595, USA.
Objective:
Use fructose-2,6-diphosphate (fru-2,6-P2) for measuring phosphofructokinase (PFK) activity in muscles.
Design And Methods:
PFK activity was measured at 2 mmol/L MgCl2 and 5 mmol/L adenosine triphosphate (ATP) (mol/L MgCl2:mol/L ATP 0.4) without and with fru-2,6-P2.
Results:
Human muscle extracts had little PFK activity when assayed at mol/L MgCl2:mol/L ATP of 0.4 to 0.78 without fru-2,6-P2; 1.83 +/- 0.91 units/g muscle. Addition of fru-2,6-P2 produced an immediate 20- to 57-fold increase in activity; 52.8 +/- 12.5 units/g muscle. Raising the mol/L ratio of MgCl2 to ATP to 0.87 and higher without fru-2,6-P2 produced 34%-76% of the PFK activity seen with fru-2,6-P2. A PFK deficiency patient had a trace of activity, which was independent of mol/L MgCl2:mol/L ATP and not activated by fru-2,6-P2.
Conclusion:
The almost complete absence of activity without fru-2,6-P2 at 0.40 mol/L MgCl2:mol/L ATP, and the restoration of maximum activity by fru-2,6-P2 provides an assay for verified PFK activity that could lead to a more accurate diagnosis in patients with PFK deficiency.
