兔磷酸激酶实验报告(英文).doc

Isolation and Enzymatic Analysis of Creatine Kinase of Rabbit Muscle Introduction Creatine kinase Creatine kinase usually exists in cytoplasm and mitochondria of organs like animal heart, muscle, brain and so on. It is an important kinase which relates to the energy operation of cells, muscle contraction and ATP regeneration. Creatine kinase reversibly catalyze phosphoryl transfer reactions between creatine and ATP. There are four forms of creatine kinase isoenzyme: MM, BB, MB, MiMi. MM mainly exists in all kinds of muscle cells, BB mainly exists in brain cells, MB mainly exists in myocardial cells while MiMi exists in the mitochondrial inner membrane. MM, BB, MiMi are plasma creatine kinase. Phosphorylation oxidative occur in the mitochondrial of cell, which produce ATP. But the high-energy material which animals use to store energy is creatine phosphate. Energy storage and transportation is complete via creatine phosphate shuttle, which include MM and MiMi. ATP produced by oxidative phosphorylation can be directly sent to the locatioin of MiMi in the outer mitochondrial membrane. MiMi transfer the high-energy phosphate bond in ATP to creatine into ADP and creatine phosphate energy material. Creatine phosphate spread in cell and reach myofibrils. The M-zone of myofibrils combines MM, thus, when muscle contracts, large amounts of ATP are required for energy supply and MM catalyst creatine phosphate into ATP. The creatine produced by the reaction will get to mitochondria and get re-phosphorylated. Creatine kinase has important physiological functions and medical applications. Muscle-type creatine kinase molecule is composed of two identical subunits dimer. In catalytic process the smallest functional unit of the enzyme is subunit which have catalysis function independently. According to the creatine kinase primary structure measured in rabbits, human, chicken, mouse recently, M-type subunit consist of 387 amino acid residues and has the molecular weight around 43 00