Brain creatine metabolism

Fig. 6.16. Electrophoretic separation of serum creatine kinase enzymes from a normal healthy adult and from a patient who had a myocardial infarction 24 hours previously. Creatine kinase catalyzes the reversible transfer of a phosphate from ATP to creatine to form phos-phocreatine and ADP. The reaction is an important part of energy metabolism in heart muscle, skeletal muscle, and brain. Three different forms of the dimer exist BB (or CK-1) found in brain, MB (or CK-2) found only in heart, and MM (or CK-3), found only in skeletal and heart muscle (cathode, — ve anode, +ve).

Magnetic resonance spectroscopy (MRS) measures the levels of different metabolites in body tissues, usually in the evaluation of nervous system disorders. Concentrations of metabolites such as N-acetyl aspartate, choline, creatine, and lactate in brain tissue can be examined. Information on levels of metabolites is usefiil in determining and dis nosing specific metabolic disorders such as Ganavan s disease, creatine deficiency, and untreated bacterial brain abscess. MRS has also been usefiil in the differentiation of high-grade from low-grade brain tumors. 

Stockier S, Holzbach U, Hanefeld F, Marquardt I, Helms G, Requardt M, Hanicke W, Frahm J. Creatine deficiency in the brain A new treatable inborn error of metabolism. Pediatr Res 1994 36 409-413... 

Figure 3 A schematic diagram of energy metabolism in skeletal muscle, heart and brain. The creatine kinase pathway is absent in liver.

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