Caracterización de dos glicosil hidrolasas de Shewanella sp. G5

CRISTÓBAL HA,; BRECCIA JD,; ABATE CM,

Rosario

Congreso; V SAMIGE; 2008

Universidad Nacional de Rosario

ß-Glucosidases (EC 3.2.1.21) are a heterogeneous group of enzymes with a broad substrate specificity range over different aryl- and alkyl-ß-D-glucosides. A Shewanella sp. G5 strain was isolate from the intestinal content of Munida subrrugosa in the Beagle Channel, Tierra del Fuego (Argentina); this marine bacteria was able to grow at 4 and 20 ºC using cellobiose as carbon source. The enzyme was quantified and expressed in UI-1(µmol min ) from assays that determined the temperature effect at 5, 10, 15, 25, 30, 37 and 45 ºC and pH effect at 3, 4,5, 6, 7, 8 and 9; using p-Nitrophenyl-ß-D-glucopyranoside (pNPG, Sigma). Zymograms assays were performed using a fluorescent substrate 4-methylumbelliferyl-ß-D-glucopiranoside (4-MU ßG, Sigma). A 100% and 80% of relative activity value were obtained at 37 ºC, pH 8; and 25 ºC, pH 6, respectively. Zymograms assays using 4-MU ßG showed the presence of two enzymes, with molecular weight about of 70 and 114 kDa respectively. These two ß-glucosidases were characterized molecularly in previous studies by the sequencing of two encoding genes.