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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Characterization of the peroxidase system at low H2O2 concentrations in isolated neonatal rat islets

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Author(s):
Stoppiglia, Luiz F. [1] ; Rezende, Luiz F. ; Ferreira, Fabiano ; Filiputti, Eliane ; Carneiro, Everardo M. ; Boschero, Antonio Carlos
Total Authors: 6
Affiliation:
[1] Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia - Brasil
Total Affiliations: 6
Document type: Journal article
Source: BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS; v. 1690, n. 2, p. 159-168, Oct. 2004.
Field of knowledge: Biological Sciences - Physiology
Abstract

B cell destruction during the onset of diabetes mellitus is associated with oxidative stress. In this work, we attempted to further trace the fate of H2O2 inside the pancreatic islets and determine whether it is mediated by enzymatic (peroxidase) activity or by chemical reaction with thiols from any protein chain. Our results suggest that the islet cells have a very similar peroxidase activity at the hydrophilic (cytoplasm) and hydrophobic compartments (organelles and nucleus), independent of the catalase content of the samples. This activity is composed of sacrificial thiols and by proteins with Fe3+/Mn3+ ions at non-heme catalytic sites. The capacity of the hydrophobic fraction to scavenge O2- was increased in the presence of high concentrations of NADP and RS and was highly dependent on RSH. On the contrary, the hydrophilic fraction exhibited a low RSH-dependent activity where the O2- scavenging is related to metal Cu2+/Fe3+/Mn3+ ions attached to the protein molecules.(AU)