Debaryomyces hansenii UFV-1 intracellular alpha-galactosidase characterization and comparative studies with the extracellular enzyme

J Agric Food Chem. 2009 Mar 25;57(6):2515-22. doi: 10.1021/jf8030919.

Abstract

Debaryomyces hansenii cells cultivated on galactose produced extracellular and intracellular alpha-galactosidases, which showed 54.5 and 54.8 kDa molecular mass (MALDI-TOF), 60 and 61 kDa (SDS-PAGE) and 5.15 and 4.15 pI values, respectively. The extracellular and intracellular deglycosylated forms presented 36 and 40 kDa molecular mass, with 40 and 34% carbohydrate content, respectively. The N-terminal sequences of the alpha-galactosidases were identical. Intracellular alpha-galactosidase showed smaller thermostability when compared to the extracellular enzyme. D. hansenii UFV-1 extracellular alpha-galactosidase presented higher kcat than the intracellular enzyme (7.16 vs 3.29 s-1, respectively) for the p-nitrophenyl-alpha-D-galactopyranoside substrate. The Km for hydrolysis of pNPalphaGal, melibiose, stachyose, and raffinose were 0.32, 2.12, 10.8, and 32.8 mM, respectively. The intracellular enzyme was a competitively inhibited by galactose (Ki = 0.70 mM), and it was inactivated by Cu(II) and Ag(I). Enzyme incubation with soy milk for 6 h at 55 degrees C reduced stachyose and raffinose amounts by 100 and 73%, respectively.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Carbohydrates / analysis
  • Debaryomyces / enzymology*
  • Enzyme Stability
  • Intracellular Space / enzymology
  • Kinetics
  • Molecular Sequence Data
  • Molecular Weight
  • Oligosaccharides / metabolism
  • Soy Milk / chemistry
  • Substrate Specificity
  • alpha-Galactosidase / chemistry*
  • alpha-Galactosidase / metabolism*

Substances

  • Carbohydrates
  • Oligosaccharides
  • alpha-Galactosidase