ATP creatine phosphate

Creatine (N-methylguanidoacetic acid) and its phosphorylated form creatine phosphate (a guanidophosphate) serve as an ATP buffer in muscle metabolism. In creatine phosphate, the phosphate residue is at a similarly high chemical potential as in ATP and is therefore easily transferred to ADP. Conversely, when there is an excess of ATP, creatine phosphate can arise from ATP and creatine. Both processes are catalyzed by creatine kinase [5]. 

Most of the coenzymes are esters of phosphoric or pyrophosphoric acid. The main reservoirs of biochemical energy, adenosine triphosphate (ATP), creatine phosphate, and phosphoenolpyruvate are phosphates. Many intermediary metabolites are phosphate esters, and phosphates or pyrophosphates are essential intermediates in biochemical syntheses and degradations. The genetic materials DNA and RNA are phosphodiesters. 

An example of a random type of reaction is creatine + ATP creatine phosphate + ADP, which is catalyzed by creatine kinase (see Chapter 20). In this case, creatine and ATP are bound to the active site in either sequence, and after the transfer of the phosphate group of the bound ATP to the bound creatine both products are released in either sequence. 

Sprinting and marathon running are powered by different fuels to maximize power output. The 100-meter sprint is powered by stored ATP, creatine phosphate, and anaerobic glycolysis. In contrast, the oxidation of both muscle glycogen and fatty acids derived from adipose tissue is essential in the running of a marathon, a highly aerobic process. 

Like ATP, creatine phosphate can be hydrolysed to yield creatine (Cr) and inorganic phosphate ( ), with a AG° of — 31 kJ. It then becomes possible for ATP and creatine to transfer phosphate groups from one to another without either needing or releasing energy. 

Creatine + ATP <=> Creatine Phosphate + ADP (catalyzed by Creatine Kinase)... 

The phosphorus cycle is one of the simplest cycles because there is no atmospheric transport of phosphorus (Figure 6.21.11). All organisms require phosphorus as a major constituent of nucleic acids, phospholipids, ATP, creatine phosphate, and (for some organisms) bones and teeth. Plants... 

ATP, creatine phosphate, and creatine kinase are added to the extract from frozen and aliquoted stocks of, respectively, 100 mM, 1 M, and 2.S mg/ml in egg lysis buffer. 

Replacement of lean body mass with fat and loss of adenosine triphosphate (ATP), creatine phosphate, glycogen, and myoglobin leave muscles weaker. 

Fleckenstein et al. (1960) have used a similar method to follow the turnover rates of 0 -labeled phosphate in muscle. ATP, creatine phosphate, and inorganic phosphate were separated by paper chromatography, eluted onto a platinum plate, and bombarded with 4 Mev protons. The activity of F formed is measured by an Nal scintillation counter, 2 hours after the end of bombardment. Nevertheless some difficulties were experienced due to nuclear side reactions, including activation of the platinum. The amount of can be calculated from the flux and the length of bombardment (see original paper), or may be determined by comparison with monitor foils with known concentrations of oxygen-18-labeled phosphate. 

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