title: Spectroscopic and thermodynamic properties of Debaryomyces hansenii UFV-1 alpha-galactosidases.
abstract: Spectroscopic and thermodynamic properties were determined for Debaryomyces hansenii UFV-1 extracellular and intracellular alpha-galactosidases. alpha-Galactosidases showed similar secondary structure compositions (alpha-helix, beta-sheet parallel and beta-turn). Effects of pH and temperature on the structure of alpha-galactosidases were investigated using circular dichroism spectroscopy. It was more pronounced at low pH. Microcalorimetry was employed for the determination of thermodynamic parameters. Immediate thermal denaturation reversibility was not observed for alpha-galactosidases; it occurred as a thermodynamically driven process. Extracellular alpha-galactosidase, at pH 5.5, showed lower T(m) when compared to the intracellular enzyme. The CD and DSC data suggest that D. hansenii alpha-galactosidases have different behaviors although they possess some similar secondary structures.
authors.affiliation: BIOAGRO, Universidade Federal de Viçosa, Viçosa, MG 36570-000, Brazil.
authors.forename: Pollyanna A
authors.initials: PA
authors.lastname: Viana
authors.forename: Sebastião T
authors.initials: ST
authors.lastname: Rezende
authors.forename: Andreia N
authors.initials: AN
authors.lastname: Meza
authors.forename: Felipe T F
authors.initials: FT
authors.lastname: Gomide
authors.forename: Ronaldo A P
authors.initials: RA
authors.lastname: Nagem
authors.forename: Alexandre M C
authors.initials: AM
authors.lastname: Santos
authors.forename: Marcelo M
authors.initials: MM
authors.lastname: Santoro
authors.forename: Valéria M
authors.initials: VM
authors.lastname: Guimarães
mesh_terms: D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D055165:Debaryomyces / Q000201:enzymology*; D005110:Extracellular Space / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D013696:Temperature; D013816:Thermodynamics; D044366:Transition Temperature; D000519:alpha-Galactosidase / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000519:alpha-Galactosidase