title: alpha-L-arabinofuranosidase production by Aspergillus nidulans.
abstract: The effects of some physico-chemical parameters on production of extracellular alpha-L-arabinofuranosidase by Aspergillus nidulans were examined. Highest levels of alpha-L-arabinofuranosidase were generated with cultures grown on 1% (w/v) purified beet pulp arabinan at 30 degrees C and at an initial pH of 7.0. The enzyme was shown to be very sensitive to the action of proteases. Zymogram overlay of a protein profile obtained by SDS-PAGE revealed the occurrence of a band (M(r) 36,000) exhibiting alpha-L-arabinofuranosidase activity. The isoelectric pH of the enzyme lay near 4.3. Temperature and pH optima for the activity of crude alpha-L-arabinofuranosidase preparations were 55 degrees C and 5.5, respectively. Enzyme activity was greatly reduced by thiol reagents such as Hg2+ and p-hydroxymercuribenzoate and showed a Km value of 2.7 mM on p-nitrophenyl alpha-L-arabinofuranoside as substrate.
authors.affiliation: Unidad de Bioingeniería, Instituto de Agroquímica y Tecnología de Alimentos, CSIC, Valencia, Spain.
authors.forename: M T
authors.initials: MT
authors.lastname: Fernández-Espinar
authors.forename: J L
authors.initials: JL
authors.lastname: Peña
authors.forename: F
authors.initials: F
authors.lastname: Piñaga
authors.forename: S
authors.initials: S
authors.lastname: Vallés
mesh_terms: D001233:Aspergillus nidulans / Q000201:enzymology*; D001426:Bacterial Proteins / Q000096:biosynthesis; D002412:Cations / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005285:Fermentation; D006026:Glycoside Hydrolases / Q000096:biosynthesis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D007700:Kinetics; D008970:Molecular Weight; D009005:Monosaccharides / Q000378:metabolism; D017672:Nitrogen Compounds / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D002412:Cations; D009005:Monosaccharides; D017672:Nitrogen Compounds; D011134:Polysaccharides; D006026:Glycoside Hydrolases; C019713:alpha-N-arabinofuranosidase