الفهرس 
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Abstract
The objective of the present study is focused on isolation of camel liver mitochondria in comparison with cattle, rabbit and rat. The activities of respiratory chain complexes were analyzed spectrophotometrically as dehydrogenases and oxidoreductases and examined polarographically as the oxygen consumption rate after addition of various substrates. By the addition of succinate, the rate of oxygen consumption increased showing State II mitochondrial respiration. However, the camel showed the lowest degree of State II respiration followed by cattle then rabbit and rat. By ADP addition, oxygen consumption (electron transport) speed up (State III respiration). The traced oxygraph showed uncoupling with no change in the slope after ADP addition in all studied species. However, there was a camel sample which showed mitochondrial coupling activity. This coupling efficiency was also more pronounced in rabbit. Km value of complex I activity in camel possessed more affinity for ubiquinone substrate than in cattle and showed decreased maximum velocity (Vmax) in all complexes when compared with cattle. The camel mitochondria seemed to be more resistant at high temperatures that explain additional acclimatization capacity to resist arid extreme temperature. In general, the present study showed that mitochondrial respiratory enzymes are differentially expressed in camel liver tissue when compared with other mammals. Examination by electron microscope demonstrated peculiar presence of large rounded sphere like globules of undefined nature in camel liver tissue that could be an extracellular energy deposits in the form of either fat or glycogen aggregates.