Uric acid, viii

Isoguanine (94), which is found in Prioneris wings along with hypoxanthine (92), xanthine (91), and uric acid (95), shows antineoplastic activities (Table VI) (57). Isolation of urocanic acid (137) from this wing material represents the first detection of this histidine derivative in an arthropod (Table VIII). A nonpteridine pigment, xanthommatin (58) (cf. Section II,B,l,b), is found in the larval body of Pieris brassicae (Table V). 

Histamine (136) is detected in mosquitoes of the genera Aedes and Culex (Culicidae) beside uric acid (95) in the former (Tables VI and VIII). Catecholamines such as adrenaline (132), noradrenaline (133), and dopamine (134) are found in the larvae of the housefly, Musca domestica (Muscidae) (Table VIII). Some pteridines are found in species of the genera Cnephia (Simuliidae) and Piophila (Piophilidae) and in other Diptera. Species of the genus Glossina (Glossinidae) contain uric acid (95) (Table VI). 

The secretion from the prothoracic glands of the lacewing Chrysopa oculata (Chrysopidae) contains skatole (140) and tridecene (Table VIII) and offers some protection against invertebrate predators, such as ants. Uric acid (95) is stored as one of the excretory products of nitrogenous metabolism in fat bodies of the larvae of C. carnea (Table VI). 

Fig. 4. Possible pathways of purine nucleotide anabolism and catabolism. The heavy arrows indicate the normal routes of degradation in man. I = phosphoribosylpyrophosphate, II = phosphoribosylamine, III = inosinic acid, IV = xanthylic acid, V = adenyhc acid, VI = guanyhc acid VII = hypoxanthine, VIII = xanthine, IX — uric acid, and X = adenosine.

The enzymic oxidation of uric acids with peroxidase (type VIII from horseradish peroxidase) has recently been studied and critically compared to the electrochemical oxidation. Peroxidase was studied because this enzyme will oxidize not only uric acid but also most of its N-methyl derivatives. Typical spectra of uric acid obtaine d during the peroxidase-catalyzed oxidation of uric acid are shown in Figure 27. Curve 1 is the spectrum of uric acid. Addition of hydrogen peroxide and peroxidase causes the initial rapid decrease of the spectrum because of dilution. However, it is quite clear from Figure 27... 

Figure 28. Cyclic voltammograms at a rough pyrolytic graphite electrode of (A) 200 fj,M uric acid in a solution contining 200 fiM H2O2, 0.5 M NaCl puls 5 mM Na2HP04, pH 7.5. Curve 1 shows initial sweep towards negative potentials. (B) Cyclic voltammogram of solution in (A) except 0.7 fiM type VIII peroxidase enzyme added. (C) Same as (B) except several minutes later. Sweep rate 200 mV s- ...

Med. CMrttrg. Tram., 1817, viii, 526, urea, uric acid 1818, ix, 472, uric acid, cystic oxide. 

Also the results found with the regeneration of leaves of Begoniaii and Cardaminei2 or with the development of ovules are interesting. They show that besides adenine and guanine, occasionally also uric acid (V), adenosine (X), adenylic acid (XI), uracil (VIII), cytosine (VI) and thymine (VII) are effective -. However, there are also some contradictory results... 

Nad. A (Tab VIII) had begun his gout when he was 1 years old He has developed huge tophie upon his sacro-iliac joints His mother had a 0% decrease of the erythrocytes HGPRTase activity She has not had, however, gouty attacks and her serum uric acid levels have been only midly elevated (7,28 mg %). He has 2 sisters who have normal enzyme levels. 

Various mono- and bistriazines have been synthesized by Moral et al. [23] under microwave conditions. The use of a diamine bearing amino groups of different reactivities, selectively gave monotriazines (vii), bistriazines with identical substituents (viii) and differently substituted bistriazines (ix). The newly synthesized bistriazines showed promising applications in supramolecular chemistry based on hydrogen bonds and/or complexation with metals. They are also expected to show interesting fluorescence properties by complexation with cyan-uric and barbituric acid derivatives. 

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