title: Purification and characterization of acid-stable protopectinase produced by Aspergillus awamori in solid-state fermentation.
abstract: Aspergillus awamori IFO 4033 produced an acid-stable protopectinase in solid-state fermentation using wheat bran as the medium. The enzyme was purified to a homogeneous preparation with anion-exchange, hydrophobic, and size-exclusion chromatography. The enzyme was a monomeric protein of 52 kDa, by SDS-PAGE analysis, with an isoelectric point of pH 3.7. The optimum pH for enzyme activity was 2.0, and it was most active at 50 degrees C (at pH 2.0) and was stable up to 50 degrees C (at pH 2.0). The enzyme showed pectin-releasing activity toward protopectins from various origins, especially on lemon protopectin. An outstanding characteristic of the enzyme was its extreme stability in acidic conditions: the enzyme activity was not lost after incubating at pH 2.0 and 37 degrees C for 24 h.
authors.affiliation: Department of Food Science and Nutrition, Faculty of Agriculture, Kinki University, Nara, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Nagai
authors.forename: A
authors.initials: A
authors.lastname: Ozawa
authors.forename: T
authors.initials: T
authors.lastname: Katsuragi
authors.forename: T
authors.initials: T
authors.lastname: Sakai
mesh_terms: D000143:Acids; D000595:Amino Acid Sequence; D001230:Aspergillus / Q000201:enzymology*; D005285:Fermentation; D006026:Glycoside Hydrolases / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D000143:Acids; D006026:Glycoside Hydrolases; C083413:protopectinase