55 by: Dixon Bertrand

Student – Dixon Bertrand

Enzyme & EC # – Phosphofructokinase; E.C. 2.7.1.11

In dogs it was found in the liver, skeletal muscles, and brain. (Kanai, et al. 2019). This enzyme is the key regulator in glycolysis. It catalyzes phosphorylation of fructose, the synthesization of fructose-6-phosphate to fructose-1,6-bisphosphate, with the use of ATP to phosphorylate both ends of fructose-6-phosphate. (Freeman, 2019; Kanai, et  al. 2019) There are two binding sites present in this enzyme for ATP. It can bind in the active site when more fructose-1,6-bisphosphate needs to be produced, or it can bind in the regulatory site to prevent the synthesization of more fructose-1,6-bisphosphate. (Freeman, 2019) This is done by altering the shape of the enzyme. (Freeman, 2019) Because of the two binding sites, this means that phosphofructokinase is an allosteric enzyme. The production of fructose-1,6-bisphosphate in phosphofructokinase is aided by fructose-2,6-bisphosphate. Fructose-2,6-bisphosphate stimulates phosphofructokinase and prevents the ATP from easily inhibiting the enzyme. (Litwack, 2018; Nelson & Cox, 2017). The synthesis of fructose-6-phosphate to fructose-1,6-bisphosphate is the first irreversible process in glycolysis, no longer able to undo the glycolysis and return to glucose. (Freeman, 2019).

References
Freeman, S., Quillin, K., Allison, L., Black, M., Podgorski, G., Taylor, E., Carmichael, J., Harrington, M., & Sharp, J. (2019). Biological science (3rd ed.). Pearson Canada.
Kanai, S., Shimada, T., Narita, T., & Okabayashi, K. (2019). Phosphofructokinase-1 subunit composition and activity in the skeletal muscle, liver, and brain of dogs. The journal of veterinary medical science, 81(5), 712-716. 10.1292/jvms.19-0049
Litwack, G. (2018) Human biochemistry. Academic Press.
Nelson, D. L., & Cox, M. M. (2017). Lehninger principles of biochemistry (7th ed.). W. H. Freeman and Company.