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| Emanuelli,T.; Bonan,C.D.; Sarkis,J.J.F.; Battastini,A.M.O.. |
| Adenosine 5',5'''-P1,P4-tetraphosphate (Ap4A) and adenosine 5',5'''-P1,P5-pentaphosphate (Ap5A) are stored in and released from rat brain synaptic terminals. In the present study we investigated the hydrolysis of dinucleotides (Ap4A and Ap5A) in synaptosomes from the cerebral cortex of adult rats. Ap4A and Ap5A, but not Ap3A, were hydrolyzed at pH 7.5 in the presence of 20 mM Tris/HCl, 2.0 mM MgCl2, 10 mM glucose and 225 mM sucrose at 37oC. The disappearance of the substrates measured by FPLC on a mono-Q HR column was both time and protein dependent. Since synaptosome integrity was at least 90% at the end of the assay, hydrolysis probably occurred by the action of an ecto-enzyme. Extracellular actions of adenine dinucleotides at central nervous system... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Ap4A; Ap5A; Diadenosine polyphosphate hydrolase; Brain synaptosomes; ApnAase. |
| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998001200003 |
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| Casali,E.A.; Silva,T.R. da; Gelain,D.P.; Kaiser,G.R.R.F.; Battastini,A.M.O.; Sarkis,J.J.F.; Bernard,E.A.. |
| Sertoli cells have been shown to be targets for extracellular purines such as ATP and adenosine. These purines evoke responses in Sertoli cells through two subtypes of purinoreceptors, P2Y2 and P A1. The signals to purinoreceptors are usually terminated by the action of ectonucleotidases. To demonstrate these enzymatic activities, we cultured rat Sertoli cells for four days and then used them for different assays. ATP, ADP and AMP hydrolysis was estimated by measuring the Pi released using a colorimetric method. Adenosine deaminase activity (EC 3.5.4.4) was determined by HPLC. The cells were not disrupted after 40 min of incubation and the enzymatic activities were considered to be ectocellularly localized. ATP and ADP hydrolysis was markedly increased by... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sertoli cells; Purine nucleotides; ATP diphosphohydrolase; Ecto-5'-nucleotidase; Ectoadenosine deaminase. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001001000003 |
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