Characterize the role
To characterize the role of ATP and phosphocreatine in providing muscular activity.
Source of energy for muscular activity is ATP (adenosine triphosphate).
Chemical energy in the process of muscle contraction is converted into mechanical work
muscles, and during relaxation provides active transport of Ca2+ in the sarcoplasmic reticulum. A large amount of ATP is consumed in the skeletal
muscles work on Na+-K+-ATPase, which maintains a certain concentration of ions Na+ and K+ in the muscle that creates the electrochemical potential on the sarcolemma.
The ATP content in muscle is insignificant and amounts to about 5 mmol • kg”1 wet weight tissue
(0,25—0,40 %). It is maintained at a relatively constant level, as the increase in the concentration of ATP in the muscles causes inhibition of ATPase of myosin, which prevents the formation of adhesions between the actin and myosin filaments in the myofibrils and muscle contractions, and decrease it below 2 mmol • kg”1 wet weight tissue leads to disruption of Ca2+- pump in the reticulum and the process of relaxation of the muscles.
The reserves of ATP in muscle fibers can ensure the implementation of intensive work only for a very short period of time of 0.5—1.5 s, or 3-4 single reductions of the maximum force. Further muscle activities are carried out thanks to the rapid recovery (recycle) ATP by high-energy postgenome substance phosphocreatine concentration which muscle is 3-4 times higher compared to ATP.
Creatine phosphate is localized directly on the contractile filaments of the myofibrils and are able to quickly react to perestrelyany with the participation of the enzyme creatine phosphokinase (CPK) .
In skeletal muscle of man CPK has a high activity, and KRF and ADP show a high chemical affinity for each other, which leads to the increase of this reaction at the beginning of muscular work, when it begins to break down ATP and accumulate ADP. Maximum power createpartcontrol reaction develops already at 0.5 to 0.7 seconds of intense work, which indicates a high speed of deployment, and maintained for 10-15 s in untrained and vysokolegirovannyh sprinters can hold 25-30 C.
Creatinphosphokinase the first mechanism is included in the process of resynthesis of ATP in the beginning of the intensive muscle work and runs at maximum speed until, until exhausted stocks of KRF in the muscles.
The metabolic capacity of this mechanism is small, because the stocks of KRF in the muscles exceeds the ATP content only 3 times. Therefore, maintaining the level of ATP by creatine phosphate is limited to its reserves, which is already on the 5-th second is reduced by 1/3, and the 15-th second — half. After that the speed createpartcontrol reaction decreases, and the resynthesis of ATP is involved glycolytic and oxidative mechanisms.
Efficiency createpartcontrol reaction is very high (76%) as the reaction proceeds directly between the two substances nameoverride. Stocks KRF depend on the content of creatine in the body. The introduction of creatine supplementation leads to an increase in stock-
owls of creatine phosphate in muscle (from 84 to 91 mmol • kg dry muscle tissue), as well as to improve physical performance. The content of creatine phosphate in skeletal muscle is increased in the process of adaptation of organism to physical speed and power loads in 1.5—2 times, which affects the capacity createpartcontrol mechanism of energy supply of muscular activity. Creatinphosphokinase path resynthesis of ATP plays a crucial role in
the supply of short-term maximum intensity for 15-30 s, for example the women’s 100 meters, swimming for short distances, jumping, throwing, weightlifting exercises, etc. It provides the ability to quickly transition from rest to work, sudden
changes of tempo during its execution, as well as the finish of acceleration. Operates creatinphosphokimasa system predominantly fast twitch muscle fibers, so is the biochemical basis of speed and local muscle strength (endurance).