Your muscular system is a complex network of tissues that relies on numerous mechanical electrical and chemical processes to function. An enzyme is a protein that acts as a catalyst in specific chemical reactions. According to "Exercise Physiology: Energy, Nutrition and Human Performance" enzymes help muscles contract and relax, allowing us to produce the force necessary to move. Different muscle enzymes act on different chemicals to accomplish various actions.
ATPase
At the cellular level, muscles are powered by the breakdown of a nucleotide called adenosine triphosphate, or ATP, which consists of an adenine molecule bonded to three phosphates. In order for ATP to be used as fuel, one of the phosphate bonds must be broken, releasing energy. In order to break this high energy bond, the enzyme ATPase degrades the ATP, releasing a phosphate and creating adenosine diphosphate or ADP.
Creatine Phosphokinase
Once ATP is degraded into ADP, it can no longer be used by muscle cells for energy and must be rebuilt into ATP. Also present in muscle cells is creatine phosphate, which consists of a creatine molecule bonded to a phosphate. In order to regenerate ATP from ADP, the enzyme creatine phosphokinase is used to take the phosphate from the creatine molecule so it can bond to ADP, creating ATP.
Acetylcholinesterase
The neuromuscular junction is where the terminal end of a nerve meets the muscle. In order for nerve impulses to reach the muscle, they must first be turned into a chemical reaction. To initiate a muscle contraction, the chemical acetylcholine is released from the end of the nerve cell. To stop the contraction, the acetylcholine must be eliminated from the neuromuscular junction. Acetylcholinesterase is an enzyme that metabolizes acetylcholine. When a muscle needs to relax following a contraction, acetylcholinesterase is released into the neuromuscular junction to quickly degrade acetylcholine, ceasing muscle contraction.
References
- "Exercise Physiology: Energy, Nutrition, and Human Performance"; William McArdle, Frank I. Katch and Victor L. Katch; 2006
- "Exercise Physiology: Theory and Application to Fitness and Performance"; Scott K. Powers and Edward T. Howley; 2006
