| Full text | |
| Author(s): |
Rustiguel, Cynthia Barbosa
[1]
;
Terenzi, Hector Francisco
[1]
;
Jorge, Joao Atilio
[1]
;
Souza Guimaraes, Luis Henrique
[1]
Total Authors: 4
|
| Affiliation: | [1] Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Biol, BR-14040901 Sao Paulo - Brazil
Total Affiliations: 1
|
| Document type: | Journal article |
| Source: | JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC; v. 67, n. 1-2, p. 10-15, NOV 2010. |
| Web of Science Citations: | 11 |
| Abstract | |
High levels of extracellular beta-D-fructofuranosidase from Aspergillus phoenicis (=Aspergillus saitoi) were obtained when the fungus was grown in Khanna medium supplemented with wheat bran as carbon source, at 40 degrees C, for 72 h. The extracellular enzyme was purified 12.5-fold to electrophoretic homogeneity, by two chromatographic steps, with a recovery of 7.5%. The purified invertase is a homodimeric glycoprotein with 1.64% carbohydrate content, native apparent molecular mass of 155 kDa and identical subunits of 79 kDa. Optima of temperature and pH were 60 degrees C and 4.5, respectively. The enzyme was stable for up to 1 h at 60 degrees C. The beta-D-fructofuranosidase activity was stimulated by Ag(+) and K(+), and inhibited by Hg(2+), Mn(2+), Mg(2+) and Na(+). The kinetic parameters (K(0.5) and V(max)), determined without or with Ag(+) and using sucrose as substrate, were 59.9 mM, 954.6U mg(-1) protein, and 29.2 mM and 1234.0 U mg(-1) protein, respectively. Only glucose and fructose were obtained as products of sucrose hydrolysis. A. phoenicis extracellular invertase is the first silver-activated beta-fructofuranosidase described in the literature. (C) 2010 Elsevier B.V. All rights reserved. (AU) | |