Abstract

CASTANON, María Mercedes; STEYERTHA, Noemí; JUAN MIGUE, Castagnino  and  GARBOSSA, Graciela. Capillary Zone Electrophoresis study of the in vitro albumin glycation process. Acta bioquím. clín. latinoam. [online]. 2006, vol.40, n.4, pp.473-482. ISSN 0325-2957.

Reducing sugars (such as glucose) can interact non-enzymatically with free amino-groups of proteins to form advanced glycation endproducts (AGEs). The objective of this work was to study the process of albumin glycation in vitro by Capillary Zone Electrophoresis (CZE). Bovine albumin (BSA; 50 mg/mL) and human serum (HS) were incubated with glucose (0.5 M) at 37 °C for 12, 24 and 60 days. Aminoguanidine (AG) was used as inhibitor (0.5 M). Afterwards, HS-albumin was separated by precipitation and redissolved in phosphate-saline buffer. Fluorescent AGEs (lexcitation=338 nm, lemission=442 nm) were detected after 12, 24 and 60 days of incubation. Fluorescence increased proportionally to the incubation times and AG was effective to inhibit the formation of fluorescent compounds. By CZE (boric acid 350 mM; pH 9,9; fused-silica gel capillary 50 µm x 50 cm; 25 kV; 90 µA; 20 °C; ldetection=200 nm) longer migration times (MT) and wider peaks (PW-50) were observed, as the incubation time was prolonged. MT and PW-50 were partially reduced in the presence of AG. It can be concluded that CZE is a highly sensitive method to detect intermediate products during the protein glycation process. This procedure can be considered complementary to the fluorometric analysis used in AGEs' study.

Keywords : advanced glycation endproducts; capillary electrophoresis; fluorometric analysis; bovine serum albumin; human serum albumin; aminoguanidine.

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