Energy metabolism creatine

FIGURE 14.21 The structures of creatine and creatine phosphate, guanidiniutn compounds that are important in muscle energy metabolism. 

Wyss, M. Smeitink, J. Wevers, R.A. Wallimann, T. Mitochondrial creatine kinase a key enzyme of aerobic energy metabolism. Biochim. Biophys. Acta, 1102, 119-166 (1992)... 

Heart. - The measurement of ATP, creatine and phosphocreatine by NMR in relation to energy metabolism of the heart in patients with cardiovascular diseases has been reviewed with 20 references. ... 

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).

Fig. 27.1. Scheme of the mitochondrial energy metabolism (in muscle tissue). The described deficiencies are indicated by numbers which refer to Table 27.1. PDH(-P)y (phosphorylated) pyruvate dehydrogenase c.I, cJI, c.III, c.IVy c.Vy complexes I, II, III, IV and V, respectively, of the respiratory chain CoQ, coenzyme Q cyt c, cytochrome c Cr(P)y creatine (phosphate) /MM, inner mitochondrial membrane OMM, outer mitochondrial membrane... 

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

Description of Method. Creatine is an organic acid found in muscle tissue that supplies energy for muscle contractions. One of its metabolic products is creatinine, which is excreted in urine. Because the concentration of creatinine in urine and serum is an important indication of renal function, rapid methods for its analysis are clinically important. In this method the rate of reaction between creatinine and picrate in an alkaline medium is used to determine the concentration of creatinine in urine. Under the conditions of the analysis, the reaction is first-order in picrate, creatinine, and hydroxide. 

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