INIBIOLP 05426
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE LA PLATA "PROF. DR. RODOLFO R. BRENNER"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Characterization of triglyceride-lipase and its natural substrates from crustacean hepatopancreas
Autor/es:
PASQUEVICH, Y.; DREON, M.; LAVARÍAS, S.; HERAS, H.
Lugar:
Tucumán- Argentina
Reunión:
Congreso; XLV Reunión Anual - Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2009
Institución organizadora:
SAIB
Resumen:
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The aim of this work was to purified and characterized a citosolic triglyceride-lipase (TG-lipase) activity from the hepatopancreas of Macrobrachium borellii. To follow the purification, a zymographic assay was used and to confirm the esterase activity measured was due to TG-lipase, the hydrolysis of 14C-TG was measured. The optimal temperature and pH values were 36°C and 8.0 respectively. The kinetic characterization of TG-lipase was done using pNPP as substrate and showed a Michaelis-Menten behavior with a Vmax=3.4x10-4 umol.min-1.mg-1 and a Km=1.63 mM. The molecular weight of the enzyme estimated by SDS-PAGE was 72 KDa. The TG pool in the M. Borellii hepatopancreas was also studied by silver nitrate chromatography allowing the separation of 4 groups hereafter named group I-IV according to their increasing R, being their FA composition analyzed by capillary GC. The group I was the major PUFA-containing one (48.5%) followed by group II (45.5%). Group III was dominated by monounsaturated FA (58.3%), and group IV had high amounts of both monounsaturated and saturated FA (50% and 45.6%, respectively).
Finally the substrate specificity of TG-lipase was determined measuring the effect of adding differrent nonradiolabeled TGs on the rate of hydrolysis of radiolabeled triolein. The enzyme showed high specificity toward TG PUFA-containing species rather than saturated ones.
