Adenosine diphosphate liver enzyme

Nishizuka Y, Ueda K, Honjo T, Hayaishi 0 (1968) Enzymic adenosine diphosphate ribosyla-tion of histone and poly(adenosine diphosphate ribose) synthesis in rat liver nuclei. J Biol Chem 243 3765-3767... 

Further purification of the second fraction showed that one of its enzymic components reacted PRPP with glutamine to yield another unidentified ribose compound and equivalent amounts of glutamic acid and pyrophosphate (86, 97). 5-Phosphoribosylamine (PRA) was believed to be the unknown compoimd, since synthetic PRA replaced the biosynthetically-formed ribose derivative in the subsequent reaction with glycine and ATP to form GAR, adenosine diphosphate (ADP), and inorganic P (98). The enzyme that catalyzed the formation of PRA from glutamine and PRPP has been purified from the soluble proteins of pigeon liver and named 5-phosphoribosylpyrophosphate amidotransferase (86). Unfortunately, it was not possible to isolate the natural product of the reaction because of extreme lability of the compound. 

It appears that most nucleotide pyrophoqihatases from mammalian tissues cleave the reduced forms of the coenzymes faster than the oxidized nucleotides. The plant nucleotide pyrophosphatases, however, q>lit DPNH, TPNH, and the oxidized coenzyme forms at equal rates. It should be pointed out, however, that an enzyme such as the potato nucleotide pyrophosphatase also attacks ATP and adenosine diphosphate (ADP), whereas the purified pigeon liver enzyme does not. The snake venom enzyme seems to split the oxidized and reduced nucleotide at equal rates. 

Nucleoside Pyrophosphates. - 2.2.1 Nucleoside Diphosphate Analogues. The enzymatic regeneration of 3 -phosphoadenosine-5 -phosphosulfate (76) catalysed by the rat liver sulfotransferase IV enzyme has been reported to provide useful quantities of the cofactor for enzyme kinetic experiments. The first thio-nucleotide analogues of adenosine 5 -phosphosulfate (77a) and of 3 -phosphoadenosine 5 -phosphosulfate (77b) have been synthesised in enantio-merically pure forms. Using these novel analogues, the sulfuryl transfer reaction to adenosine 5 -triphosphate was shown to proceed with inversion of configuration at the a-phosphorus. ... 

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