Cellular energetics

It is the complexity ofthe array of enzymes, coenzymes and intermediates which at first sight provides a daunting barrier to those wishing to try to understand cellular energetics. 

The increase in erythrocyte destruction may be due in part to inhibition by lead of pyrimidine-5 -nucleotidase, which results in an accumulation of pyrimidine nucleotides (cytidine and uridine phosphates) in the erythrocyte or reticulocyte. This enzyme inhibition and nucleotide accumulation affect erythrocyte membrane stability and survival by alteration of cellular energetic (Angle et al. 1982 EPA 1986a). Formation of the heme-containing cytochromes is inhibited in animals treated intraperitoneally or orally... 

For a more detailed examination of the role of mitochondria in cellular energetics, see G. Brown, The Energy of Life The Science of What Makes Our Minds and Bodies Work, The Free Press, New York, 2000. 

B. Banerjee, U. Sharma, K. Balasubramanian, M. Kalaivani, V. Kalra and N. R. Jagannathan, Effect of creatine monohydrate in improving cellular energetics and muscle strength in ambulatory Duchenne muscular dystrophy patients a randomized, placebo-controlled 31P MRS study. Magn. Reson. Imaging, 2010,28,698-707. 

A short, clearly written account of cellular energetics, including introductory chapters on thermodynamics. 

Nucleophilic displacements on phosphorus (Table 10-1, reaction type 1C) are involved in virtually every aspect of cellular energetics and in many aspects of biosynthesis. One large group of such enzymes are phosphotransferases, which transfer phospho (also called phosphono or, traditionally in biochemistry, phosphoryl) groups from one nucleophilic center to another. When transfer is to water the enzymes are called phosphatases, and when from one group in a molecule to another in the same molecule, mutases. 

Broda, E., The Evolution of Bioenergetic Processes. New York Pergamon Press, 1975. An excellent discussion of cellular energetics from an evolutionary perspective. 

Rissanen, E., Krumschnabel, G. and Nikinmaa, M. (2003) Dehydroabietic acid, a major component of wood industry effluents, interferes with cellular energetics in rainbow trout hepatocytes, Aquatic... 

Freyer, J.P., Schor, P.L., Jarrett, K.A., Neeman, M., Sillerud, L.O. (1991). Cellular energetics measured by phosphorous nuclear magnetic resonance spectroscopy are not correlated with chronic nutrient deficiency in multicellular tumor spheroids. Cancer Res. 51,3831-3837. 

D. A. Beard. Modeling of oxygen transport and cellular energetics explains observations on in vivo cardiac energy metabolism. PloS Comput. Biol., 2 el07, 2006. 

Humes HD, Weinberg JM. 1983. Cellular energetics in acute renal failure. In Brenner BM, Lazarus JM, eds. Acute renal failure. Philadelphia, PA W.B. Saunders, 47-98. 

PARP inhibitors can be used to maintain cellular energetics. They do this by preventing NAD depletion, which helps prevent ATP depletion. In addition, inhibited PARP remains bound to DNA and is less vulnerable to the actions of caspase-3. This helps prevent necrosis and apoptosis. 

Nicotinamide, but not niacin, is taken up into the brain by an active uptake process (31) and is converted into NAD (Fig. 11.9). Niacin released in the brain from catabolic processes is converted into nicotinamide as shown. Nicotinamide can increase brain levels of NAD by 50% or more (32). By increasing brain NAD levels, nicotinamide prevents ATP depletion (9) and protects cellular DNA (32). Therefore, nicotinamide maintains cellular energetics in the presence of oxidative stress. 

Many compounds have been investigated that may maintain cellular energetics, especially in pellagra (Fig. 11.10). All but one of the compounds found to be active can be converted into NAD in the body (33). This is important because compounds that make NAD... 

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