Biochemical characterization of an ectonucleotide pyrophosphatase/phosphodiesterase (E-NPP, E.C. 3.1.4.1) from rat cardiac soluble and microsomal fractions |
| |
| Authors: | Pochmann Daniela Innocente Adrine Maria Buffon Andréia Freitas Sarkis João José Porciúncula Lisiane De Oliveira |
| |
| Affiliation: | Laboratório de Estudos sobre o Sistema Purinérgico, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. danipochmann@hotmail.com |
| |
| Abstract: | In this study, we have reported the kinetic and biochemical characterization of ectonucleotide pyrophosphatase/phosphodiesterase (E-NPP) activity in rat cardiac fractions, one soluble and the other enriched in vesicles derived from sarcoplasmic reticulum. Both fractions demonstrated E-NPP activities, which could be observed by extracellular hydrolysis of p-nitrophenyl-5'-thymidine monophosphate (p-Nph-5'-TMP) and other biochemical characteristics. The K(M) values for the hydrolysis of p-Nph-5'-TMP in soluble and microsomal fractions were 118.53?±?27.28 and 91.92?±?12.49 μM, respectively. The V(max) values calculated were 2.56?±?0.15 and 113.87?±?21.09 nmol p-nitrophenol/min/mg of protein in soluble and microsomal fractions, respectively. Among the compounds tested to evaluate the possible activity of other enzymes on p-Nph-5'-TMP hydrolysis, only suramin (0.25?mM) produced a significant inhibition of substrate hydrolysis. Thus, our results strongly suggest the presence of E-NPP enzymes in subcellular fractions of rat heart, which could be involved in nucleotide signalling in the cardiac tissue. |
| |
| Keywords: | |
| 本文献已被 PubMed 等数据库收录！ |
|
