title: Alkali-tolerant high-activity catalase from a thermophilic bacterium and its overexpression in Escherichia coli.
abstract: We have purified an alkali-tolerant catalase from the thermophilic bacterium Metallosphaera hakonensis. The catalase gene, which encodes 303 amino acids and has a calculated molecular mass of 33 kDa, including its putative signal peptide encoding sequence, was cloned. The deduced amino acid sequence exhibited a region-specific homology with the sequences of manganese catalases from thermophilic bacteria such as Thermus thermophilus and Thermus brockianus. When this gene was overexpressed in Escherichia coli, proteins of the expected size (33 kDa) were overproduced in the inactive form. We made several attempts to obtain active forms of or to activate these overproduced proteins. Upon their induction into E. coli, a 100-fold increase in the catalase activity was detected when high-concentration manganese was used as the medium. The catalase activity of the purified enzyme was optimal at a pH of 10.0. The alkali-tolerant property of this catalase makes it a promising enzyme in biotechnological applications such as H(2)O(2)-detoxifying systems.
authors.affiliation: Aisin Cosmos R&D Co. Ltd., 2-1-5 Kazusa-kamatari, Kisarazu, Chiba 292-0818, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Ebara
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Shigemori
mesh_terms: D000468:Alkalies / Q000494:pharmacology*; D002374:Catalase / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000302:isolation & purification; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008345:Manganese / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D019810:Sodium Azide / Q000494:pharmacology; D016943:Sulfolobaceae / Q000187:drug effects / Q000201:enzymology*
chemical_list: D000468:Alkalies; D011994:Recombinant Proteins; D008345:Manganese; D019810:Sodium Azide; D002374:Catalase