PT - JOURNAL ARTICLE AU - Pérez-Gilabert, Manuela AU - Téllez, Edgar AU - García-Carmona, Francisco TI - Triton X-114-aided Extraction and Partial Characterization of β-Galactosidase from Grape Berry Pulp (<em>Vitis vinifera</em> L.) AID - 10.5344/ajev.2009.60.3.368 DP - 2009 Sep 01 TA - American Journal of Enology and Viticulture PG - 368--372 VI - 60 IP - 3 4099 - http://www.ajevonline.org/content/60/3/368.short 4100 - http://www.ajevonline.org/content/60/3/368.full SO - Am J Enol Vitic.2009 Sep 01; 60 AB - β-Galactosidase from grape berry pulp was extracted after a 2 hr digestion with the non-ionic detergent Triton X-114. Subsequent phase partitioning eliminated ~75% of the phenolic compounds, enabling the enzyme to be recovered in the aqueous upper phase with an 8-fold increase in its specific activity. The enzyme was kinetically characterized using o-nitrophenyl β-galactopyranoside as substrate and was active at acidic pH with an optimum at pH 4.2, a value at which Vmax and Km were 0.009 μmol/min/mg protein and 1.2 mM, respectively. β-Galactosidase was competitively inhibited by free galactose with Ki of 0.8 mM. The enzyme had an optimum temperature of 65°C, although its thermostability is very low at this temperature.