Characterization and biotechnological application of an acid alpha-galactosidase from Tachigali multijuga Benth. seeds.
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. alpha-Galactosidase activity increased during seed germination and reached a maximum level at 108 h after seed imbibition. The alpha-galactosidase purified from germinating seeds had an M(r) of 38,000 and maximal activity at pH 5.0-5.5 and 50 degrees C. The enzyme was stable at 35 degrees C and 40 degrees C, but lost 79% of its activity after 30 min at 50 degrees C. The activation energy (E(a)) values for p-nitrophenyl-alpha-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 HgCl(2), SDS, AgNO(3), CuSO(4), 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.
Departamento de Bioquímica e Biologia Molecular - BIOAGRO, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil.
Lílian da Silva
Lda S
Fialho
Valéria Monteze
VM
Guimarães
Carina Marin
CM
Callegari
Angélica Pataro
AP
Reis
Daianny Silveira
DS
Barbosa
Eduardo Euclydes de Lima
EE
Borges
Maurilio Alves
MA
Moreira
Sebastião Tavares
ST
de Rezende
D007887:Fabaceae / Q000201:enzymology*; D018525:Germination; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D009844:Oligosaccharides / Q000378:metabolism; D012639:Seeds / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature; D000519:alpha-Galactosidase / Q000302:isolation & purification* / Q000378:metabolism*
D009844:Oligosaccharides; D000519:alpha-Galactosidase