Clinical Aspects

The condition known as fatal infantile mitochondrial myopathy and renal dysfunction involves severe diminution or absence of most oxidoreductases of the respiratory chain. MELAS (mitochondrial encephalopathy, lactic acidosis, and stroke) is an inherited condition due to NADH:ubiquinone oxidoreductase (complex I) or cytochrome oxidase deficiency. It is caused by a muta-

INNER

CYTOSOL MEMBRANE MITOCHONDRION

INNER

CYTOSOL MEMBRANE MITOCHONDRION

Figure 12-13. Malate shuttle for transfer of reducing equivalents from the cytosol into the mitochondrion. ©Ketoglutarate transporter; ©, glutamate/aspartate transporter (note the proton symport with glutamate).

Figure 12-14. The creatine phosphate shuttle of heart and skeletal muscle. The shuttle allows rapid transport of high-energy phosphate from the mitochondrial matrix into the cytosol. CKa, creatine kinase concerned with large requirements for ATP, eg, muscular contraction; CKj, creatine kinase for maintaining equilibrium between creatine and creatine phosphate and ATP/ADP; CKg, creatine kinase coupling glycolysis to creatine phosphate synthesis; CKm, mitochondrial creatine kinase mediating creatine phosphate production from ATP formed in oxidative phosphorylation; P, pore protein in outer mitochondrial membrane.

Energy-requiring

___processes

(eg, muscle contraction)

ATP ADP

Creatine

ATP ADP

Creatine-P

Creatine

Creatine-P

Inter-membrane space

ATP ADP

Inter-membrane space

ATP ADP

tion in mitochondrial DNA and may be involved in Alzheimer's disease and diabetes mellitus. A number of drugs and poisons act by inhibition of oxidative phosphorylation (see above).

Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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