Phosphofructokinase-1 (PFK-1) is a major factor in process known as glycolysis. PFK-1 catalyzes the committed step, or begins an irreversible enzymatic reaction, which is the point of no return. PFK-1 also regulates triacylglycerol synthesis, which helps decrease the amount of fat storage. By preventing PFK-1 from doing its job, other glycolytic intermediaries decrease such as 2,3-bisphosphoglycerate.
Defective Phosphofructokinase-1 
Faulty PFK-1 can cause a build up of glucose, glucose-6-phosphate, and other glycolytic intermediaries. The end result of this is glycogen synthesis, which can lead to increased solute concentration in red blood cells, enlarged spleen, a swelled heart, and ultimately death.
1. "Phosphofructokinase-1." Phosphofructokinase-1. N.p., n.d. Web. 07 Dec. 2012.