Phosphofructokinase-1 subunit composition and activity in the skeletal muscle, liver, and brain of dogs

Phosphofructokinase-1 (EC:2.7.1.11, PFK-1) catalyzes the phosphorylation of fructose 6-phosphate to fructose 1,6-bisphosphate using adenosine triphosphate and is a key regulatory enzyme of glycolysis. Mammalian PFK-1 isozymes are composed of three kinds of subunits (PFK-M, -L, and -P), with different properties. It has been suggested that the proportion of PFK-1 subunits in different organs is based on the organ energy metabolism. In this study, we analyzed the activity and subunit composition of canine PFK-1. We found that, in dogs, the skeletal muscle only has PFK-M, the liver mainly has PFK-L, and the brain expresses all of them. The knowledge of the composition of PFK-1 could provide useful information for determination of the differences in glycolysis in various organs of dogs.