Adenine structural formula

Adenine is a weak base. Which one of the three nitrogens designated by arrows in the structural formula shown is protonated in acidic solution A resonance evaluation of the three protonated forms will tell you which one is the most stable. 

Chemical Name 9-/3-D-arabinofuranosyl-9H-purine-6-amine monohydrate Common Name Adenine arablnoside spongoadenosine Structural Formula ... 

FIGURE 10.1 The structural formula of riboflavin and partial structures of riboflavin compounds. The latter show only those portions of the molecule that differ from riboflavin. 1 — Riboflavin (RF), 2 — flavin mononucleotide or 5 -riboflavin monophosphate (FMN or 5 -FMN), 3 — flavin adenine dinucleotide (FAD). 

Problem 22.47 Write the structural formulas for adenine monophosphate (amp) and triphosphate (atp) nucleotides, (atp is the most important source of energy for biochemical processes in living tissues the energy comes from the breaking of the high-energy polyphosphate bonds.)... 

Figure 4.7 Structural formula of nicotinamide adenine dinucleotide in its reduced form of NADH + H+ and its oxidized form NAD+.

An important aspect of enzymatic oxidation-reduction reactions involves the transfer of hydrogen atoms. This transfer is mediated by coenzymes (substances that act together with enzymes) nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). These two species pick up H atoms to produce NADH and NADPH, respectively, both of which can function as hydrogen atom donors. Another pair of species involved in oxidation-reduction processes by hydrogen atom transfer consists of flavin adenine triphosphate (FAD) and its hydrogenated form FADH2. The structural formulas of NAD and its cationic form, NAD+, are shown in Figure 4.7. 

Figure 1. Structural formulae (/3-form shown) and overall redox reaction of nicotinamide adenine dinucleotide, NAD+, and its reduced form, the enzymatically active 1,4-NADH. Reproduced with permission from ref. 35. Copyright 1991 Elsevier Science Publishers.

The three pyrimidine bases are uracil, thymine, and cytosine, usually abbreviated U, T, and C. Adenine (A) and guanine (G) are the two purine bases. Adenine, guanine, and cytosine are found in both DNA and RNA, but uracil is ordinarily found only in RNA, and thymine only in DNA. Structural formulas of the five bases are given in I Figure 11.3. 

Rgure 2 Structural formulae of two enzyme cofactors (A) nicotinamide adenine dinucleotide (NAD) and (B) flavin adenine dinucleotide (FAD) with the corresponding redox transformations in dehydrogenases and oxidases catalyzed reaction, respectively. NAD is a soluble cofactor and it has to be added to the reaction mixture. As shown in Figure 1, FAD is bound to the flavoprotein. 

Write structural formulas showing how the keto form of uracil (Section 25.2) in mRNA PRACTICE PROBLEM 25.9 can pair with adenine in DNA through hydrogen bond formation. 

Draw a structural formula for the /3-/V-glycoside formed between 6-D-ribofuranose and adenine. 

When NAD acts as an oxidizing agent, it is reduced to NADH, which, in turn, is a reducing agent and is oxidized to NAD. In these abbreviated structural formulas, the adenine dinucleotide part of each molecule is represented by the symbol Ad ... 

Fig. 6 Proposed structural formulas and redox reaction of the electrooxidixed adenine moiety of NAD acting as an efficient mediator for NADH oxidation [139].

Five organic bases (amines) are most often found in nucleotides. The bases are adenine, guanine, cytosine, uracil, and thymine. They link to the sugars through the indicated nitrogen (in color) in each of the following structural formulas ... 

Figure 1 Structural formulae of riboflavin, FMN, and FAD (1) riboflavin in oxidized (FL j) or reduced form (FL, ) (2) FMN, flavin mononucleotide (3) FAD, flavin adenine dinucleotide. ...

Figures 2 and 3 show simplified structural formulas of adenine and adenosine complexes, respectively. The structures of the complexes reflect the pronounced tendency of purines to act as bridging ligands. Binding sites of adenine differ with metal ion variation. Evidence from IR, electronic spectra, and magnetic susceptibilities reported previously suggest structures for the complexes vary both with the central metal and the nature of the ligand.

Additive toxic effects, 25 213—214 Adducts, of vinyl chloride, 25 632 Adenine, 8 174. See also ADP entries Adenocard, molecular formula and structure, 5 98t... 

Nicotine adenine dinucleotide phosphate (NADP+), 24 147 Nicotinic acid, 9 477-478 26 291 alkaloid precursor, 2 78 Ni-Cr alloys, 23 499. See also Nickel-chromium entries NiCrAlY coatings, 13 508 nido designation boranes, 4 184-186 boron hydrides, 4 170, 172-176 Nidrel, molecular formula and structure, 5 129t... 

Purine derivatives are considered to be prebiotic molecules. Purine as well as adenine (HCN) can be formed from hydrogen cyanide in the presence of ammonia in a prebiotic atmosphere. Similar reaction in the presence of water can lead to other purines. Purine chemistry goes back to the roots of organic chemistry. Uric acid was the first purine isolated from bladder stones by Scheelc in 1776. The correct empirical formula of uric acid was established much later by Liebig and Mitscherlich. The correct structure was suggested by L. Medicus and was shown to be correct by the syntheses ofHorbaezewski. Behrend and Roosen, and unambiguously by E. Fischer. The development of purine chemistry by E. Fischer is a milestone in heterocyclic chemistry. 

The antibiotic nucleocidin (28) is produced by Streptomyces calvus (n. sp) that was isolated from a soil sample obtained in Dinepur, India. Dilute-acid hydrolysis of nucleocidin yields adenine and a six-carbon, reducing sugar. Its ultraviolet spectrum indicates that it is a 9-substituted adenine, and its empirical formula is CnHieNeOsS. A partial structure of nucleocidin (28) has been proposed. ... 

Nicotinamide adenine dinucleotide, one of the most important coenzymes (Section 24.9) in biological oxidations and reductions, includes both a pyridine derivative (nicotinamide) and a purine derivative (adenine) in its structure. Its formula is shown in Fig. 14.23 as NAD , the oxidized form that contains the pyridinium aromatic ring. The reduced form of the coenzyme is NADH, in which the pyridine ring is no longer aromatic due to presence of an additional hydrogen and two electrons in the ring. 

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