RT Journal Article SR Electronic T1 Triton X-114-aided Extraction and Partial Characterization of β-Galactosidase from Grape Berry Pulp (Vitis vinifera L.) JF American Journal of Enology and Viticulture JO Am J Enol Vitic. FD American Society for Enology and Viticulture SP 368 OP 372 DO 10.5344/ajev.2009.60.3.368 VO 60 IS 3 A1 Manuela Pérez-Gilabert A1 Edgar Téllez A1 Francisco García-Carmona YR 2009 UL http://www.ajevonline.org/content/60/3/368.abstract 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.