Answer to Question #154388 in Biochemistry for Reece E Monk

Question

What would happen to an organism that lacked the enzyme that catalyzes the first step in glycolysis? 

Answer 1

The enzyme that catalyzes the first step of glycolysis is Phosphofructokinase (PFK), which converts fructose-6-phosphate to fructose-1,6-bisphosphate. The two initial phosphorylations by hexokinase and PFK require ATP and are therefore irreversible. PFK is one of the key regulators in glycolysis. Glycolysis is a metabolic pathway and an anaerobic energy source that has evolved in almost all types of organisms. Although it doesn't require oxygen, hence its purpose in anaerobic respiration, it is also the first step in cellular respiration. The process entails the oxidation of glucose molecules, the single most crucial organic fuel in plants, microbes, and animals. Most cells prefer glucose (although there are exceptions, such as acetic acid bacteria that prefer ethanol). In glycolysis, 2 ATP molecules are consumed, with the production of 4 ATP, 2 NADH, and 2 pyruvates per molecule of glucose. The pyruvate can be used in the citric acid cycle or serve as a precursor for other reactions.

If an organism lacks this enzyme (PFK), then it cannot carry out this single most important step of life, hence will die.