(Brazilian Archives of Biology and Technology, 2005-03) Rezende, Sebastião Tavares de; Guimarães, Valéria Monteze; Rodrigues, Marília de Castro; Felix, Carlos Roberto
Aspergillus fumigatus secreted invertase (b-fructofuranosidase) and a-galactosidase enzymatic activities able to hydrolyzing raffinose oligosaccharides (RO). a-Galactosidase was induced by galactose, melibiose and raffinose, but galactose was the most efficient inducer. It was purified by gel filtration and two ion exchange chromatographies and showed Mw of 54.7 kDa. The purified enzyme showed maximal activity against p-nitrophenyl-a-D-galactopyranoside (pNPGal) at pH 4.5-5.5 and 55 °C, and retained about 80% of the original activity after incubation for 90 minutes at 50ºC. The KM for pNPGal was 0.3 mM. Melibiose was hydrolyzed by the enzyme but raffinose was very poor substrate.
