title: New alkalophilic β-galactosidase with high activity in alkaline pH region from Teratosphaeria acidotherma AIU BGA-1.
abstract: A β-d-galactosidase exhibiting high activity in the alkaline pH region was purified from Teratosphaeria acidotherma AIU BGA-1, which we previously isolated as a unique fungal producer of three acidophilic and one alkalophilic β-d-galactosidases (Isobe et al., J. Biosci. Bioeng., 116, 171-174, 2013). The enzyme was stable in the pH range 7.5-10.0 and exhibited optimal activity at pH 8.0 and 60°C. The enzyme hydrolyzed 2-nitrophenyl β-d-galactopyranoside, 4-nitrophenyl β-d-galactopyranoside, and lactose, and the Kmvalues were estimated to be 0.349 mM, 0.488 mM, and 701 mM, respectively. Chelating reagents (EDTA and o-phenanthroline) and metals (Cu2+and Ni2+) inhibited the enzyme activity, and Mn2+was a good activator. The enzyme also exhibited transgalactosylation activity for lactose. The enzyme's molecular mass was estimated to be 180 kDa, and its structure was monomeric. Thus, the enzymatic and physicochemical characteristics of the alkalophilic β-galactosidase in this study clearly differed from those of the previously known alkalophilic β-d-galactosidases.
authors: Department of Biological Chemistry and Food Science, Iwate University, Ueda-3, Morioka 020-8550, Japan.
authors: Miwa
authors: M
authors: Yamada
authors: Department of Biological Chemistry and Food Science, Iwate University, Ueda-3, Morioka 020-8550, Japan.
authors: Serina
authors: S
authors: Chiba
authors: Department of Biological Chemistry and Food Science, Iwate University, Ueda-3, Morioka 020-8550, Japan.
authors: Yuta
authors: Y
authors: Endo
authors: Department of Biological Chemistry and Food Science, Iwate University, Ueda-3, Morioka 020-8550, Japan. Electronic address: kiso@iwate-u.ac.jp.
authors: Kimiyasu
authors: K
authors: Isobe
mesh_terms: D001203:Ascomycota / Q000201:enzymology*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability; D005690:Galactose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D007785:Lactose / Q000378:metabolism; D008670:Metals / Q000494:pharmacology; D008970:Molecular Weight; D009596:Nitrophenols / Q000378:metabolism; D010618:Phenanthrolines / Q000378:metabolism; D013696:Temperature; D001616:beta-Galactosidase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D008670:Metals; D009596:Nitrophenols; D010618:Phenanthrolines; C024719:4-nitrophenyl; D001616:beta-Galactosidase; D007785:Lactose; C025205:1,10-phenanthroline; D005690:Galactose
keywords: Alkalophilic lactase; Lactase; Lactose; Teratosphaeria acidotherma; β-Galactosidase