title: Purification, characterization, and molecular cloning of tyrosinase from Pholiota nameko.
abstract: Tyrosinase (monophenol, 3,4-dihydroxy L-phenylalanine (L-DOPA):oxygen oxidoreductase, EC 1.14.18.1) was isolated from fruit bodies of Pholiota nameko and purified to homogeneity. The purified enzyme was a monomer with a molecular weight of 42,000 and contained 1.9 copper atoms per molecule. The N-terminal of the purified enzyme could not be detected by Edman degradation, probably due to blocking, while the C-terminal sequence of the enzyme was determined to be -Ala-Ser-Val-Phe-OH. The amino acid sequence deduced by cDNA cloning was made up of 625 amino acid residues and contained two putative copper-binding sites highly conserved in tyrosinases from various organisms. The C-terminal sequence of the purified enzyme did not correspond to that of the deduced sequence, but agreed with Ala384-Ser385-Val386-Phe387 in sequence. When the encoded protein was truncated at Phe387, the molecular weight of the residual protein was calculated to be approximately 42,000. These results suggest that P. nameko tyrosinase is expressed as a proenzyme followed by specific cleavage to produce a mature enzyme.
authors.affiliation: Division of Biosciences, Graduate School of Fundamental Life Science, Kitasato University, Sagamihara. Kanagawa, Japan. konishi@ishikawa-pu.ac.jp
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Kawamura-Konishi
authors.forename: Mariko
authors.initials: M
authors.lastname: Tsuji
authors.forename: Seiichi
authors.initials: S
authors.lastname: Hatana
authors.forename: Masahiro
authors.initials: M
authors.lastname: Asanuma
authors.forename: Dai
authors.initials: D
authors.lastname: Kakuta
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kawano
authors.forename: Etsuko B
authors.initials: EB
authors.lastname: Mukouyama
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Goto
authors.forename: Haruo
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D000363:Agaricales / Q000201:enzymology*; D000364:Agaricus / Q000201:enzymology; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D014442:Monophenol Monooxygenase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D014442:Monophenol Monooxygenase