Barbara Cellini

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G41 is an interfacial residue located within the alpha-helix 34-42 of alanine:glyoxylate aminotransferase (AGT). Its mutations on the major (AGT-Ma) or the minor (AGT-Mi) allele give rise to the variants G41R-Ma, G41R-Mi, and G41V-Ma causing hyperoxaluria type 1. Impairment of dimerization in these variants has been suggested to be responsible for(More)
The hepatic peroxisomal alanine:glyoxylate aminotransferase (AGT) is a pyridoxal 5'-phosphate (PLP)-enzyme whose deficiency is responsible for Primary Hyperoxaluria Type 1 (PH1), an autosomal recessive disorder. In the last few years the knowledge of the characteristics of AGT and the transfer of this information into some pathogenic variants have(More)
Exposure of rabbit red blood cells to dehydroascorbic acid (DHA) caused a significant decline in glutathione content which was largely prevented by quercetin, whereas it was insensitive to various antioxidants, iron chelators or scavengers of reactive oxygen species. This response was not mediated by chemical reduction of either extracellular DHA or(More)
Human hepatic peroxisomal AGT (alanine:glyoxylate aminotransferase) is a PLP (pyridoxal 5'-phosphate)-dependent enzyme whose deficiency causes primary hyperoxaluria Type I, a rare autosomal recessive disorder. To acquire experimental evidence for the physiological function of AGT, the K(eq),(overall) of the reaction, the steady-state kinetic parameters of(More)
The sensitivity to denaturant stress of the major (AGT-Ma) and the minor (AGT-Mi) allele of alanine:glyoxylate aminotransferase and P11L mutant has been examined by studying their urea-induced equilibrium unfolding processes with various spectroscopic and analytical techniques. AGT-Ma loses pyridoxal 5'-phosphate (PLP) and unfolds completely without(More)
Many human diseases are caused by genetic mutations that decrease protein stability. Such mutations may not specifically affect an active site, but can alter protein folding, abundance, or localization. Here we describe a high-throughput cell-based stability assay, IDESA (intra-DHFR enzyme stability assay), where stability is coupled to cell proliferation(More)
STAT3 is a latent transcription factor that promotes cell survival and proliferation and is often constitutively active in cancers. Although many reports provide evidence that STAT3 is a direct target of oxidative stress, its redox regulation is poorly understood. Under oxidative conditions STAT3 activity can be modulated by S-glutathionylation, a(More)
Primary Hyperoxaluria Type I (PH1) is a disorder of glyoxylate metabolism caused by mutations in the human AGXT gene encoding liver peroxisomal alanine:glyoxylate aminotransferase (AGT), a pyridoxal 5'-phosphate (PLP) dependent enzyme. Previous investigations highlighted that, although PH1 is characterized by a significant variability in terms of enzymatic(More)
The role of insulin-like growth factor 1 (IGF1) pathway as regulator of aging and age-related diseases is increasingly recognized. Recent evidence has been provided that neuronal IGF1-R increases during aging leading to activation of a signaling pathway that causes an increased production of amyloid β-peptide, the principal event in the pathogenesis of(More)
The unusual oxygen-consuming oxidative deamination reaction catalyzed by the pyridoxal 5'-phosphate (PLP) enzyme DOPA decarboxylase (DDC) was here investigated. Either wild-type or Y332F DDC variant is able to perform such oxidation toward aromatic amines or aromatic l-amino acids, respectively, without the aid of any cofactor related to oxygen chemistry.(More)