title: Purification and properties of beta-galactosidase from Aspergillus oryzae.
abstract: Beta-Galactosidase [EC 3.2.1.23] has been purified from a culture of Aspergillus oryzae by 2-propanol fractionation, column chromatography on DEAE-Sephadex A-50 and Sephadex G-200. The preparation was homogeneous on ultracentrifugation and disc electrophoresis. The enzyme showed pH optima of 4.5 with ONPG-1 as a substrate and 4.8 with lactose as a substrate. The stable pH range was from 4.0 to 9.0 and the optimum temperature was 46 degrees. The Michaelis constants were 7.2 X 10-minus 4 M with ONPG and 1.8 X 10-minus 2 M with lactose. Hg-2+, Cu-2+, N-bromosuccinimide, and sodium laurylsulfate caused marked inhibition. The apparent molecular weight was calculated to be about 105,000 by Sephadex gel filtration and sucrose density gradient centrifugation.
mesh_terms: D000433:1-Propanol; D000596:Amino Acids / Q000032:analysis; D001230:Aspergillus / Q000201:enzymology*; D001236:Aspergillus oryzae / Q000201:enzymology*; D001974:Bromosuccinimide / Q000494:pharmacology; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003300:Copper / Q000494:pharmacology; D004589:Electrophoresis, Disc; D005696:Galactosidases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008628:Mercury / Q000494:pharmacology; D008970:Molecular Weight; D009598:Nitrophenylgalactosides; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013696:Temperature
chemical_list: D000596:Amino Acids; D009598:Nitrophenylgalactosides; D012967:Sodium Dodecyl Sulfate; D003300:Copper; D000433:1-Propanol; D005696:Galactosidases; D008628:Mercury; D001974:Bromosuccinimide