NAD metabolism

NAD Metabolism Chromatin structure Cell stress responses Apoptosis Aging... 

Di Lisa F, Ziegler M. Pathophysiological relevance of mitochondria in NAD metabolism. FEBS Utt 2001 492 4-8. 

Williams GT, Lau KMK, Coote JM, Johnstone AP (in press) NAD metabolism and mitogen stimulation of human lymphocytes. Exp Cell Res... 

To better understand the involvement of NAD and poly(ADP-ribose) metabolism during the early stage of MAM acetate treatment NAD metabolism was studied. 

The cellular content of NAD the substrate for poly(ADP-ribose) polymerase is probably one of the important factors regulating the enzyme activity. Several studies relate the significance of NAD metabolism to the poly(ADP-ribosyl)ation status of the acceptor proteins under a variety of experimental conditions (13). We find here (Table 3) that there is an inverse relationship between the levels of poly(ADP-ribose) polymerase activity and NAD levels of Ewing s sarcoma and laryngeal squamous cell carcinoma and lung carcinoma as compared to normal human fibroblasts. 

Fig. 1. (left) Effect of ethanol on poly(ADP-ribose) and NAD metabolism in vivo. SV40 transformed mouse 3T3 cells were grown as previously described (6) and treated with 20 pg/ml MNNG and 1% ethanol was added to some cultures. Poly(ADP-ribose) (panel A) and NAD (panel B) were extracted and quantified as described elsewhere (6). 

Our laboratories have investigated NAD metabolism in both prokaryotic and eukaryotic systems. Background information in this area has previously been reviewed (1-3). The work we describe here on eukaiyotic systems is initial experiments to examine the possible role of ADP-ribosylation in modulating synaptic transmission in die nervous system, hi this article, we also summarize our present understanding of NAD metabolism and its regulation in the bacterium Salmonella typhimurium, and present preliminary data for a link between NAD turnover cycles and DNA repair in this bacterium. 

NAD also serves as a substrate for ADP-ribosyl transferases. Mono-ADP-ribosyl transferases appear to function mainly in the cytoplasm where they may be involved in regulatory functions such as allosteric modifiers. Poly(ADP-ribose) synthesis is important in regulation of nuclear events, in particular, the DNA repair process interference with poly(ADP-ribose) synthesis has an inhibitory effect on DNA repair synthesis. Thus, NAD metabolism, ADP-ribosylation and the interrelation of these processes serve as important connections between regulation of nuclear events and control of a wide variety of cellular processes. The central regulatory role of pyridine... 

The Effect of Extracellular Calcium on NAD Metabolism in Human Diploid Cells... 

Thus, in the cell, the newly synthesized NAD is faced with several foes, and the cell must either provide NAD at a rate more rapid than that at which the coenzyme is hydrolyzed, or the new NAD must be kept separate from the catabolic enzymes. The intracellular distribution of the enzymes involved in NAD metabolism, therefore, is of capital interest. The enzyme that catalyzes the formation of deamido NAD from ATP and nicotinic acid mononucleotide is in the nucleus, as was first shown by Hogeboom and Schneider [93]. Later, Elyane Baltus also demonstrated that, at least in the starfish, this reaction is restricted to the nucleolus [94]. 

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