Adenosine, modified

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). ... 

Adenosine Modified with Boron Cluster Pharmacophores as a New Human... 

Dismption of the endothehal surface of blood vessels expose coUagen fibers and connective tissue. These provide surfaces that promote platelet adherence, platelet release reaction, and subsequent platelet aggregation. Substances Hberated from the platelets stimulate further platelet aggregation, eg, adenosine diphosphate maintain vasoconstriction, eg, serotonin and participate in blood coagulation, eg, platelet Factors III and IV. In addition, the release reaction modifies platelet membranes in a manner that renders phosphoHpid available for coagulation. The thrombin [9002-04-4] elaborated by the coagulation mechanism is a potent agent in the induction of the platelet release reaction. 

Poly(ethylene glycol) (PEG) molecules attached to adenosine deaminase (ADA) have been used in patients exhibiting symptoms of the severe combined immunodeficiency syndrome (SCID) caused by ADA deficiency. The modified enzyme has a plasma half-life of weeks as compared to the unmodified enzyme (minutes) (248). PEG-L-asparaginase has induced remissions in patients with non-Hodgkin s lymphoma (248). However, one disadvantage of PEG-enzyme treatment is its expense, ie, a year s treatment costs about 60,000 (248). 

Further computational studies on adenines and adenosines concern the reaction mechanism of ribonuclease A with cytidyl-3,5 -adenosine [99BP697] and the molecular recognition of modified adenine nucleotides [99JMC5338]. 

To correlate embryonic arrests with the metabolic pathways, and especially to understand why cellular organelles first undergo chemical damages, biological investigations include evaluation of DNA, RNA, protein, glucose, lipid, and adenosine-5 -triphosphate (ATP) contents, whose fractions are extracted and isolated by modified Schneider methods. In particular,... 

PARHAMI F, FANG Z T, FOGELMAN A M, ANDALIBI A, TERRITO M C and BERLINER J A (1993) Minimally modified low density lipoprotein-induced inflammatory responses in endothelial cells are mediated by cyclic adenosine monophosphate /owmaZ of Clinical Investigation 92, 471-8. 

Acid-catalyzed matrices, kinetics of controlled release, 170-179 Active targeting, definition, 276 Adenosine deaminase, activity of polyethylene glycol modified enzymes, 98-99 Adjuvax... 

Figure 12.1 Extracellular adenosine concentrations in different brain areas, measured with in vivo microdialysis from cats during sleep deprivation (6 h gentle handling) and recovery sleep. Concentrations are given as a percentage of pre-deprivation values. BF, basal forebrain CX, cingulate cortex TH, VA/VL nucleus of thalamus POA, preoptic hypothalamic area DRN, dorsal raphe nucleus PPT, pedunculopontine nucleus. In BF and CX adenosine rises during sleep deprivation, but starts to decline during deprivation in CX, whereas the decline occurs during recovery in the BF. In other areas there is no accumulation during sleep deprivation. Modified from Porkka-Heiskanen et al. (2000).

RaitVK, Zhang Q,Fabris D,et al. Conversions of formaldehyde-modified 2 -deoxy-adenosine 5 -monophosphate in conditions modeling formalin-fixed tissue dehydration. I. Histochem. Cytochem. 2006 54 301-310. 

A photoreactive nucleotide, 8-bromo-2 -deoxy-adenosine, was incorporated post-synthetically into a DNA sequence (35, Fig. 13) within the previously determined DNA contact site for the transcription factor. Upon irradiation the resulting nitrene cross-linked primarily to the 50-kDa subunit and covalently modified Lys-244. On the other hand, that amino acid residue appeared not... 

Figure 6.1 Pathways involved in glucose oxidation by plant cells (a) glycolysis, (b) Krebs cycle, (c) mitochondrial cytochrome chain. Under anoxic conditions. Reactions 1, 2 and 3 of glycolysis are catalysed by lactate dehydrogenase, pyruvate decarboxylase and alcohol dehydrogenase, respectively. ATP and ADP, adenosine tri- and diphosphate NAD and NADHa, oxidized and reduced forms of nicotinamide adenine dinucleotide PGA, phosphoglyceraldehyde PEP, phosphoenolpyruvate Acetyl-CoA, acetyl coenzyme A FP, flavoprotein cyt, cytochrome e, electron. (Modified from Fitter and Hay, 2002). Reprinted with permission from Elsevier...

Histone ADP-ribosylation was first reported in 1968 [290]. Poly(ADP-ribosylation) has been implicated in several nuclear processes, including DNA replication, repair and recombination [291-294]. Histone HI and the four core histones are modified by adenosine diphospho (ADP) ribosylation which involves the transfer of the ADP-ribose moiety of NAD" " to the histone acceptor (Figs. 1 and 2). HI is the principle poly(ADP-ribosylated) histone, while core histones are ADP-ribosylated to a minor extent [295-297]. HI is modified at Glu residues 2, 14 (or 15), and 116 (or 117) and at Lys located at the C-terminus [25,298,299]. Poly(ADP-ribosylated) HI is associated with dynamically acetylated core histones [295]. There is conflicting results as to whether poly(ADP-ribosylation) of HI promotes chromatin decondensation [300-304]. 

Substances with a neuromodulatory effect on brain neurotransmitters by direct actions of specific receptors that modify the actions of the transmitters listed include prostaglandins, adenosine, enkephalins, substance P, cholecystokinin, endorphins, endogenous benzodiazepine receptor ligands, and possibly histamine. CNS, central nervous system. NMDA, N-methyl-D-aspartate. Strych, strychnine. 

Nucleic acid degradation in humans and many other animals leads to production of uric acid, which is then excreted. The process initially involves purine nucleotides, adenosine and guanosine, which are combinations of adenine or guanine with ribose (see Section 14.1). The purine bases are subsequently modified as shown. 

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