Adenosine 5 -phosphate, AMP

Kinoshita, Imoto etal.11 14) synthesized other anionic models, 5 (APVP), CPVP, UPVP, TPVA, HPVA, THPVA, and 6 (AMPPVA), by the polymer reaction of N-eoupled(2-dihydrogenphosphate)-ethylderivatives of nucleic acid bases (or adenosine-5 -phosphate, AMP) with polyvinylaleohol. A, C, U, T, H, and TH denote adenine, cytosine, uracil, thymin, hypoxanthine, and theophylline, respectively. The authors reported the apparent hypochromities of 3 to 16% for many kinds of mixtures of the models and DNA or RNA, as compiled in Table 1. However, for the mixtures APVA + RNA, HPVA + RNA HPVA + DNA, THPVA + RNA, CPVA + DNA and CPVA + RNA, no hypochromicity was detected. 

Adenine Adenosine-5 -phosphate (AMP) Deoxyadenosine-5 -phosphate (dAMP)... 

An intriguing use of the oxidative potential stored in thianthrene radical ion(l-l-) is provided by the formation of high-energy phosphate bonds. Thus, the interaction of adenosine-5 -phosphate (AMP) and orthophos-phoric acid, each as their ammonium salts, with two equivalents of thi-... 

Muscular work is accompanied by the production of ammonia, the immediate source of which is adenosine 5 -phosphate (AMP).301 302 This fact led to the recognition of another substrate cycle (Chapter 11) that functions by virtue of the presence of a biosynthetic pathway and of a degradative enzyme in the same cells (cycle A, Fig. 25-17). This purine nucleotide cycle operates in the brain303 304 as well as in muscle. The key enzyme 5-AMP aminohydrolase (AMP deaminase step a, Fig. 25-17) also occurs in erythrocytes and many other tissues.304 305 Persons having normal erythrocyte levels but an absence of this enzyme in muscles suffer from muscular weakness and cramping after exercise.306... 

One possibility for understanding the Py-MS results for nucleic acids is to use a parallel between the mass spectral fragmentation and the pyrolysis fragmentation. This can be exemplified for the mass spectra of the silylated 2 -deoxyadenosine-5 -phosphate (deoxy-AMP) and adenosine-5 -phosphate (AMP), which are shown in Figure 13.1.1 and 13.1.2 respectively (El spectra at 70 eV). The interpretation of several fragments in these spectra is given in Table 13.1.1. 

Nucleotidase (EC 3.1,3.5 5 -ribonucleotide phosphohy-drolase NTP) is a phosphatase that acts only on nucleoside-5 -phosphates, such as adenosine-5 -phosphate (AMP) and adenyhc acid, releasing inorganic phosphate. 

Sessler and coworkers have recently developed a high-performance liquid chromatography (HPLC) support with sapphyrin-functionalized silica gel [67]. Oxyanions were found to interact with the sapphyrin unit, and thus they were retained longer compared to an appropriate control support. The separations of adenosine, adenosine 5 -phosphate (AMP), adenosine 5 -diphosphate (ADP) and ATP, and dimers to nonamers of polydeoxyadenylic acids at neutral pH were also achieved. 

In spite of their biological and agricultural importance, only in the last decade the basic molecular mechanism of their biosynthesis and signal transduction have been elucidated. The first step in the isoprenoid CK biosynthesis is the M-prenylation of adenosine-5 -phosphate (AMP, ADP, or ATP) with DMAPP or hydroxymethylbutenyl diphosphate (HMBDP) catalyzed by adenosine phosphate-isopentenyltransferase (IPT). Plant IPTs preferentially utilize ATP or ADP as the isoprenoid acceptors to form isopentenyl riboside 5 -triphosphate (iPRTP) and... 

The final amino acid to be considered here is histidine (His, H). As shown in Scheme 12.26, the initial steps begin with the reaction of ribose-1,5-diphosphate with ATP in the presence of ATP-phosphoribosyl transferase (EC 2.4.2.17) then, after phosphate is lost (phosphoribosyl-ATP diphosphatase [EC 3.6.1.31]), the pyrimidine ring is hydrolytically cleaved (phosphoribosyl-adenosine 5 -phosphate [AMP] cyclohydrolase [EC 3.5.4.19]), a process that is followed by the opening of... 

The conversion of IMP to AMP requires amination at C-6 of the purine system, and the nitrogen for this process is derived from aspartate (Asp, D) (adenylosuccinate synthase, EC 6.3.4.4). It appears that the driving force for the loss of water in this process that yields N -l, 2-dicarboxyl adenosine monophosphate (adenosine 5 -phosphate, AMP) is the conversion of guanosine triphosphate (GTP) to guano-sine diphosphate (GDP). Adenosine monophosphate (adenosine 5 -phosphate, AMP) is formed from the N -derivative by loss of fumarate (catalyzed by adenylosuccinate lyase, EC 4.3.2.2). 

The dinucleotide NAD" (and NADH, NAD(P)", and NAD(P)H) is composed of ADP and a second ribosyl unit to which a nicotinamide is appended at the anomeric carbon. The biosynthesis of adenosine monophosphate (adenosine 5 -phosphate, AMP) was outlined above, and AMP can be converted to ADP by the action of adenylate kinase (EC 2.7.4.3). The enzymes called ATP synthases (EC 3.6.3.14 and 3.6.3.15) are complicated membrane- and nonmembrane-associated species that convert the energy associated with proton electrochemical gradients into ATP from ADP and inorganic phosphate (Pi) (Chapter 14). 

Scheme 14.2. A repetition of Scheme 12.97, serving to generate adenosine 5 -phosphate (AMP) via inosine 5 -phosphate (IMP). EC nnmbers and some graphic materials in this scheme have been taken from appropriate links in a URL starting with http7/ www.chem.qmul.ac.uk/inbmb/enzyme. 

Adenosine-5 -phosphate (AMP) can be estimated by converting all of the ATP, ADP, and AMP into ATP with creatine adenylic transphosphorylase (10) and excess creatine phosphate (Fig. 3). From the total ATP thus obtained the amount of AMP can be calculated by difference. 

Glutamic acid is oxidized to completion by the kidney and liver cyclo-phorase suspensions of Green and co-workers (P). The oxidation is associated with aerobic phosphorylation, and requires the presence of adenosine 5 -phosphate (AMP), Mg++, and P. Since aged preparations are stimulated by DPN+ it appears highly probable that cyclophorase preparations contain L-glutamate dehydrogenase and enzymes of the TCA cycle. 

The C-1 of ribose 5-P was incoiporated into imidazoleglycerol phosphate without dilution. When AMP-8-C was employed, the aminoribosyl-imidazolecarbnxamide phosphate had the same radioactivity as the reisolated adenosine 5-phosphate (AMP) the imidazol ycerol phosphate had no detectable activity. The C-2 of adenine, on the contrary, was incorporated into imidazoleglycerol ph q>hate without dilution, but was not incorporated into the aminoribosylimidazolecarboxamide phosphate. 

Means were also sought of increasing the rate of incorporation and/or prolonging the life of the homogenates by studying their metabolic requirements. These were found to be rather similar to those of slices, in that substrates for respiration and oxidative phosphorylation were required. Besides adenosine 5 -phosphate (AMP), PO", Mg++, K+, and Ca++ also had a stimulatory effect (73, 74)- These requirements will become clearer when the requirements of the individual suboellular fractions are discussed. 

This diminished the effectiveness of fully protected intermediates unless rapid deprotection could be carried out. It was much better if a lower degree of protection was utilized. Thus, a set of methods for activation of monoesters, for example, adenosine 5 -phosphate (AMP), were developed (Scheme 4), Dicyclohexylcarbodiimide (8) and arene-sulfonyl chlorides led rapidly to symmetrical pyrophosphates (8) (11). Michelson found that (PhO)2 PO Cl gave activated intermediates (9) that were on the verge of stability, but could be put into reaction with a second component to obtain the required unsymmetrical polyphosphate (10) (12). The complete solution to the problem depended on forming phosphoramidic acids (11) (and related structures), stable in themselves but capable of undergoing reaction by cleavage of the P—bond (Scheme A) (6,13). Phosphates are better nucleophiles than... 

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