Adenosine diphosphate ADP -ribose

Certain bacterial exntoxins are enzymes that attach the adenosine diphosphate (ADP)-ribose residue of NAD to Ga subunits, an activity known as ADP-ribosylation ... 

Humans have metabolic pathways that are able to recycle NAD. The main pathway is catalysed by ADP-ribosyltransferases, which participate in nonredox adenosine diphosphate (ADP)-ribose transfer reactions. These NAD-consuming enzymes break down NAD to nicotinamide and ADP-ribosyl product. Nicotinamide is then retransformed to NAD by the enzymatic action... 

Non-redox Adenosine Diphosphate (ADP)-Ribose Transfer Reactions... 

NAD/NADP have also shown to be required for important non-redox adenosine diphosphate (ADP)-ribose transfer reactions involved in DNA repair, calcium mobilization and deacetylation reactions (Lautier et al. 1993 Poliak et al. 2007) (Figure 7.5). 

Deoxyribonucleotides, the building blocks of DNA, are derived from the corresponding ribonucleotides by direct reduction at the 2 -carbon atom of the D-ribose to form the 2 -deoxy derivative. For example, adenosine diphosphate (ADP) is reduced to 2 -deoxyadenosine... 

Figure 16.1 The structure of adenosine triphosphate (ATP). The lower ring is a ribose sugar, the upper molecule is the base, adenine. Adenosine diphosphate (ADP) differs from ATP by having two phosphate groups attached instead of three.

Adenine Ribose Adenosine Adenylic acid adenosine monophosphate (AMP) Adenosine diphosphate (ADP) Adenosine triphosphate (ATP)... 

ATP is a nucleotide consisting of an adenine, a ribose, and a triphosphate unit (Figure 14.3). The active form of ATP is usually a complex of ATP with Mg2+ or Mn2+ (Section 9.4.2). In considering the role of ATP as an energy carrier, we can focus on its triphosphate moiety. ATP is an energy-rich molecule because its triphosphate unit contains two phosphoanhydride bonds. A large amount of free energy is liberated when ATP is hydrolyzed to adenosine diphosphate (ADP) and orthophosphate (Pj) or when ATP is hydrolyzed to adenosine monophosphate (AMP) and pyrophosphate... 

Figure 14.19. Adenosine Diphosphate (ADP) Is an Ancient Module in Metabolism. This fundamental building block is present in key molecules such as ATP, NADH, FAD, and coenzyme A. The adenine unit is shown in blue, the ribose unit in red, and the diphosphate unit in yellow.

The first two questions are relatively simple to answer. Adenosine, it will be remembered, is the nucleotide formed from adenine and ribose, and it can be phosphorylated to yield first adenosine monophosphate (AMP), then adenosine diphosphate (ADP) and finally ATP (see page 41). If we follow the course of its hydrolysis back to adenosine we find the following series of reactions ... 

The formation of deoxyribonucleotides requires ribonucleotide reductase activity, which catalyzes the reduction of ribose on nucleotide diphosphate substrates to 2 -deoxyribose. Substrates for the enzyme include adenosine diphosphate (ADP), guanosine diphosphate (GDP), cytidine diphosphate (CDP), and uridine diphosphate (UDP). Regulation of the enzyme is complex. There are two major allosteric sites. One controls the overall activity of the enzyme, whereas the other determines the substrate specificity of the enzyme. All deoxyribonucleotides are synthesized using this one enzyme. 

Figure 7.5 Adenosine diphosphate (ADP)-ribosylation biochemical reactions. Mono-ADP-ribosyltransferases (ARTs) and poly-ADP-ribose pol5mierases Poly (PARPs) catalyse the ADP-ribose moiety of NAD transfer to amino acid residues. ADP-ribosyl cyclases generate cyclic ADP-ribose and 2-phospho-cyclic ADP-ribose from NAD and NADP, respectively. Both molecules trigger cyclic ADP-ribose cytosolic Ca " elevation, presumably by activating the ryanodine receptor in the endoplasmic/sarcoplasmic reticulum (RER). SIRTl catalyses a reaction that couples protein deacetylation to NAD hydrolysis.

A 5-carbon sugar—a pentose—synthesized by the body in all animals, including man. Hence, it is not essential in the diet, but in the body ribose plays an important role. When it is joined with pyrimidines—cytosine, thymine, and uracil and purines—adenine and guanine—nucleosides are formed. When phosphoric acid is esterified with the nucleosides, nucleotides are formed. These compounds are then used in the formation of ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). The nucleotides of adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP) are compounds that are essential to cellular metabolism. Ribose is also a constituent of the vitamin riboflavin. 

Further purification of the second fraction showed that one of its enzymic components reacted PRPP with glutamine to yield another unidentified ribose compound and equivalent amounts of glutamic acid and pyrophosphate (86, 97). 5-Phosphoribosylamine (PRA) was believed to be the unknown compoimd, since synthetic PRA replaced the biosynthetically-formed ribose derivative in the subsequent reaction with glycine and ATP to form GAR, adenosine diphosphate (ADP), and inorganic P (98). The enzyme that catalyzed the formation of PRA from glutamine and PRPP has been purified from the soluble proteins of pigeon liver and named 5-phosphoribosylpyrophosphate amidotransferase (86). Unfortunately, it was not possible to isolate the natural product of the reaction because of extreme lability of the compound. 

A relatively nonspecific adenyl deaminase has been purified from Aspergillus oryeae which deaminates, in descending order of rate, adenosine, adenosine 5 -phosphate, adenosine 3 -phosphate, ATP, adenosine diphosphate (ADP), DPN, DPNH, and adenosine-diphosphate-ribose. Adenine, TPN, and adenosine 2 -phosphate are unaltered by the enzyme (29). A... 

The sirtuins (silent information regulator 2-related proteins class III HDACs) form a specific class of histone deacetylases. First, they do not share any sequence or structural homology with the other HDACs. Second, they do not require zinc for activity, but rather use the oxidized form of nicotinamide adenine dinucleotide (NAD ) as cofactor. The reaction catalyzed by these enzymes is the conversion of histones acetylated at specific lysine residues into deacetylated histones, the other products of the reaction being nicotinamide and the metabolite 2 -0-acetyl-adenosine diphosphate ribose (OAADPR) [51, 52]. As HATs and other HDACs, sirtuins not only use acetylated histones as substrates but can also deacetylate other proteins. Intriguingly, some sirtuins do not display any deacetylase activity but act as ADP-ribosyl transferases. 

This enzyme [EC 2.4.2.30] (also referred to as NAD+ ADP-ribosyltransferase, poly(ADP) polymerase, poly-(adenosine diphosphate ribose) polymerase, and ADP-ribosyltransferase (polymerizing)) catalyzes the reaction of NAD+ with [ADP-D-ribosyl] to produce nicotinamide and [ADP-D-ribosyl]( + i). The ADP-d-ribosyl group of NAD+ is transferred to an acceptor carboxyl group on a histone or on the enzyme itself, and further ADP-ribosyl groups are transferred to the 2 -position of the terminal adenosine moiety, building up a polymer with an average chain length of twenty to thirty units. 

Adenosine 5 -phosphate. See AMP Adenosine diphosphate. See ADP Adenosine monophosphate. See AMP Adenosine triphosphate. See ATP Adenosine-diphosphate-ribose. See ADP-ribose... 

ADP (Adenosine diphosphate) 536 in adenylate system 302 - 304 complexes with metal ions 296 dissociation as acid 288 intracellular concentration 304 P-31 NMR spectrum 642 pka value of 293 in regulation 535 ADP-ribose (ADPR) 315, 778, 780 ADP-ribosylation 545, 778 ADP-ribosylation factors (ARFs) 559 Adrenaline (epinephrine) 534, 542, 553, 553s in adrenergic receptor 535 a-Adrenergic receptors 553, 558, 563 p-Adrenergic receptors 553, 554 in asthma 553 in heart failure 553 receptor kinase 553 structure (proposed) 534, 555 topology 555... 

To establish the SAR analysis of adenosine diphosphates (hydroxyme-thyl)pyrrolidinediol inhibition of poly(ADP-ribose) glycohydrolase, Jacobson has synthesised a series of guanosine- and adenosine-modified pyrrolidinediol pyrophosphates (238a-j). ... 

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