title: Purification and characterization of polygalacturonase produced by thermophilic Thermoascus aurantiacus CBMAI-756 in submerged fermentation.
abstract: An extracellular polygalacturonase was isolated from 5-day culture filtrates of Thermoascus aurantiacus CBMAI-756 and purified by gel filtration and ion-exchange chromatography. The enzyme was maximally active at pH 5.5 and 60-65 degrees C. The apparent K (m) with citrus pectin was 1.46 mg/ml and the V (max) was 2433.3 micromol/min/mg. The apparent molecular weight of the enzyme was 30 kDa. The enzyme was 100% stable at 50 degrees C for 1 h and showed a half-life of 10 min at 60 degrees C. Polygalacturonase was stable at pH 5.0-5.5 and maintained 33% of initial activity at pH 9.0. Metal ions, such as Zn(+2), Mn(+2), and Hg(+2), inhibited 50, 75 and 100% of enzyme activity. The purified polygalacturonase was shown to be an endo/exo-enzyme, releasing mono, di and tri-galacturonic acids within 10 min of hydrolysis.
authors.affiliation: Biologia, Universidade Estadual paulista-UNESP, Instituto de Biociências, Letras e Ciências Exatas-IBILCE, R: Crsitovao Colombo, 2265, Jardim Nazareth, São José do Rio Petro, São Paulo, 15054-000, Brazil.
authors.forename: Eduardo Silva
authors.initials: ES
authors.lastname: Martins
authors.forename: Denis
authors.initials: D
authors.lastname: Silva
authors.forename: Roberto
authors.initials: R
authors.lastname: da Silva
authors.forename: Rodrigo S R
authors.initials: RS
authors.lastname: Leite
authors.forename: Eleni
authors.initials: E
authors.lastname: Gomes
mesh_terms: D001203:Ascomycota / Q000145:classification / Q000201:enzymology*; D005285:Fermentation / Q000502:physiology; D011096:Polygalacturonase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D011096:Polygalacturonase