Main content area

Characterization and biotechnological application of an acid α-galactosidase from Tachigali multijuga Benth. seeds

Fialho, Lilian da Silva, Guimaraes, Valeria Monteze, Callegari, Carina Marin, Reis, Angelica Pataro, Barbosa, Daianny Silveira, Borges, Eduardo Euclydes de Lima, Moreira, Maurilio Alves, Rezende, Sebastiao Tavares de
Phytochemistry 2008 v.69 no.14 pp. 2579-2585
Tachigali, seeds, seed germination, alpha-galactosidase, enzyme activity, thermal stability, enzyme inhibition, metal ions, enzyme substrates, oligosaccharides, enzymatic hydrolysis, substrate specificity, soymilk, locust bean gum, guar gum
Tachigali multijuga Benth. seeds were found to contain protein (364 mg g-1 dwt), lipids (24 mg g-1 dwt), ash (35 mg g-1 dwt), and carbohydrates (577 mg g-1 dwt). Sucrose, raffinose, and stachyose concentrations were 8.3, 3.0, and 11.6 mg g-1 dwt, respectively. α-Galactosidase activity increased during seed germination and reached a maximum level at 108 h after seed imbibition. The α-galactosidase purified from germinating seeds had an Mr of 38,000 and maximal activity at pH 5.0-5.5 and 50 °C. The enzyme was stable at 35 °C and 40 °C, but lost 79% of its activity after 30 min at 50 °C. The activation energy (E(a)) values for p-nitrophenyl-α-d-galactopyranoside (pNPGal) and raffinose were 13.86 and 4.75 kcal mol-1, respectively. The K(m) values for pNPGal, melibiose, raffinose, and stachyose were 0.45, 5.37, 39.62 and 48.80 mM, respectively. The enzyme was sensitive to inhibition by HgCl2, SDS, AgNO3, CuSO4, and melibiose. d-Galactose was a competitive inhibitor (K(i) = 2.74 mM). In addition to its ability to hydrolyze raffinose and stachyose, the enzyme also hydrolyzed galactomannan.