Energy metabolism substrates

Complexes III and IV have Fe-porphyrin prosthetic groups (hemes), complex IV also contains copper atoms which are involved in electron transport. Complexes I, III, and IV use the energy of electron transport to pump protons out of the matrix so as to maintain a pH gradient and an electrical potential difference across the inner membrane required for ATP synthesis (see below and Appendix 3). It is important to remember that all dehydrogenations of metabolic substrates remove two protons as well as two electrons and that a corresponding number of protons are consumed in the final reduction of dioxygen (Figures 5, 6). 

Glucose is the main obligatory substrate for energy metabolism 536... 

Defects of energy metabolism cause profound disturbances in the function of muscle and brain. Such defects may present as a myopathy, encephalopathy or encephalo-myopathy. Clinical features are best appreciated by understanding the preferred oxidizable substrates for brain and muscle. 

Flint, A., Raben, A., Ersboll, A.K., Holst, J.J. and Astrup, A. (2001) The effect of physiological levels of glucagons-like peptide-1 on appetite, gastric emptying, energy and substrate metabolism in obesity. International Journal of Obesity, 25, 781-792. 

Adrenal medulla. On the one hand, release of epinephrine elicits cardiovascular effects, such as increases in heart rate und peripheral vascular resistance. On the other, it evokes metabolic responses, such as glycogenolysis and li-polysis, that generate energy-rich substrates. The sensation of hunger is suppressed. The metabolic state corresponds to that associated with physical exercise - silent stress . 

The only metabolic activity that has been for decades ascribed to the trichomonad hydrogenosome was related to energy metabolism. It has been unequivocally shown that, under anaerobic conditions, isolated intact hydrogenosomes produced roughly equimolar amounts of acetate, CO2, and hydrogen from pyruvate in a process accompanied by substrate-level phos-... 

Apart from the utilization of the common mono- and di-saccharides as metabolic substrates for growth and energy, there is little information on the growth effects of externally applied carbohydrates. Some, like D-mannose, D-galactose, and 2-deoxy-D-araWno-hexose, are inhibitory to root growth,718 possibly because they provide a high osmotic concentration in solution, from which they are only indifferently utilized, without being actively phytotoxic. 

Apparently, parasitic flatworms have discarded some pathways of de novo lipid synthesis, but have selectively retained several biosynthetic pathways that modify host lipids. Although lipids like fatty acids and cholesterol are obtained from the host, less abundant lipids that are more difficult to acquire because of their low concentration in the host (e.g. specific unsaturated fatty acids, eicosanoids, ecdysteroids and quinones) are synthesized de novo by the parasite, usually by the modification of more abundant substrates. In this way, lipid metabolism of parasitic flatworms is adapted to an opportunistic way of life, just like their energy metabolism. 

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