Lehninger Principi Di Biochimica Pdf Free
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Questo sito contiene le risorse per lo studente e le risorse per il docente collegate a I principi di biochimica di Lehninger, settima edizione di David L. Nelson, Michael M. Cox.
Xanthine (3,7-dihydro-purine-2,6-dione), is a purine base found in most human body tissues and fluids and in other organisms. A number of stimulants are derived from xanthine, including caffeine and theobromineXanthine is a product on the pathway of purine degradation.It is created both from guanine by guanine deaminase that from adenosine by adenosine deaminase. Purine nucleotides are degraded by a sequence of reactions in which the phosphate group is lost by the action of 5'-nucleotidase. The adenylate is converted into adenosine, which is then deaminated to inosine by adenosine deaminase. The inosine is hydrolyzed in its purine base hypoxanthine and D-ribose. The free hypoxanthine is subsequently oxidized to xanthine and then to uric acid by xanthine oxidase, a flavoenzima that contains in his prosthetic group one atom of molybdenum and iron-sulfur centers . The catabolism of GMP generates uric acid as a final product. The GMP is first hydrolyzed to form the nucleoside guanosine, which is then cleaved releasing the guanine. The free base is removed by hydrolysis of the amino group, generating xanthine that is converted to uric acid by xanthine oxidase. (David L. Nelson - Michael M. Cox, I principi di biochimica di Lehninger, V edizione). 1e1e36bf2d