Adenosine triphosphate higher-energy

Adenosine triphosphate creatine A-phosphotransferase (EC 2.7.3.2), also creatine phosphokinase. Creatine kinase is found in muscle and is responsible for the formation of creatine phosphate from creatine and adenosine triphosphate creatine phosphate is a higher energy source for muscle contraction. Creatine kinase is elevated in all forms of muscular dystrophy. Creatine kinase is dimer and is present as isozymes (CK-1, BB CK-2, MB CK-3, MM) and Ck-mt (mitochondrial). Creatine kinase is also used to measure cardiac muscle damage in myocardial infarction. See Bais, R. and Edwards, J.B., Creatine kinase, CRC Crit. Rev. Clin. Lab. ScL 16, 291-355, 1982 McLeish, M.J. and Kenyon, G.L., Relating structure to mechanism in creatine kinase, Crit. Rev. Biochem. Mol. Biol 40, 1-20, 2005. 

Figure 1 An example of the way metallo-enzymes are under controlled formation through both controlled uptake (rejection) of a metal ion and controlled synthesis of all the proteins connected to its metabolism and functions. The example is that of iron. Iron is taken up via a molecular carrier by bacteria but by a carrier protein, transferrin, in higher organisms. Pumps transfer either free iron or transferrin into the cell where Fe + ions are reduced to Fe + ions. The Fe + ions form heme, aided by cobalamin (cobalt 2 controls) and a zinc enzyme for a-laevulinic acid (ALA) synthesis. Heme or free iron then goes into several metallo-enzymes. Free Fe + also forms a metallo-protein transcription factor, which sees to it that synthesis of all iron carriers, storage systems, metallo-proteins, and metallo-enzymes are in fixed amounts (homeostasis). There are also iron metallo-enzymes for protection including Fe SOD (superoxide dismutase). Adenosine triphosphate (ATP) and H+ gradients supply energy for all processes. See References 1 -3.

The need for energy by the cell regulates the tricarboxylic acid cycle, which acts in concert with the electron transfer chain and the ATPase to produce adenosine triphosphate in the inner mitochondrial membrane. The cell has limited amounts of ATP, adenosine diphosphate (ADP), and adenosine monophosphate (AMP). When ADP levels are higher than ATP, the cell needs energy, and hence NADH is oxidized rapidly and the tricarboxylic acid cycle is accelerated. When the ATP level is higher than ADP, the cell has the energy needed hence, the electron transport chain slows down. 

In rabbits with experimentally induced stenosis of the aorta, papaverine injected i.v. caused a return of the decreased level of dehydrogenase of lactic acid to normal values (43). Higher concentrations of papaverine had a significant inhibitory effect on the utilization of energy from adenosine-5 -triphosphate (ATP) in experiments on rat... 

---