title: A cold-adapted tyrosinase with an abnormally high monophenolase/diphenolase activity ratio originating from the marine archaeon Candidatus Nitrosopumilus koreensis.
abstract: OBJECTIVE
  To obtain an acidic and cold-active tyrosinase, which potentially minimizes unwanted self-oxidation of tyrosinase-catalyzed catechols, including 3,4-dihydroxyphenylalanine at elevated pH and high temperature.
  
  
  RESULTS
  A putative psychrophilic tyrosinase (named as tyrosinase-CNK) was identified from the genome information of the marine archaeon Candidatus Nitrosopumilus koreensis. This protein contains key tyrosinase domains, such as copper-binding domains and an O2-binding motif, and phylogenetic analysis revealed that it was distinct from other known bacterial tyrosinases. Functional tyrosinase-CNK was produced by applying a co-expression strategy together with chaperone proteins in Escherichia coli with a yield of approx. 30 mg l(-1) and a purity >95 %. The purified enzyme showed optimal activity at pH 6 and 20 °C and still had 50 % activity at 0 °C. Surprisingly, the enzyme exhibited an abnormally high monophenolase/diphenolase activity ratio.
  
  
  CONCLUSIONS
  The acidic and cold-adapted tyrosinase-CNK, as a new type of tyrosinase, could expand potential applications of tyrosinases including the production of catechols through minimizing unwanted self-oxidation and the modification of existing materials at low temperature.
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, 305-764, Korea.
authors.forename: Hyerin
authors.initials: H
authors.lastname: Kim
authors.affiliation: School of Chemical and Biological Engineering, Seoul National University, Seoul, 151-742, Korea.
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Yeon
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, 305-764, Korea.
authors.forename: Yoo Rae
authors.initials: YR
authors.lastname: Choi
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, 305-764, Korea.
authors.forename: Wooho
authors.initials: W
authors.lastname: Song
authors.affiliation: Department of Biotechnology and Bioinformatics, Korea University, Sejong, 339-700, Korea. spack@korea.ac.kr.
authors.forename: Seung Pil
authors.initials: SP
authors.lastname: Pack
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon, 305-764, Korea. biochoi@cnu.ac.kr.
authors.forename: Yoo Seong
authors.initials: YS
authors.lastname: Choi
mesh_terms: D001105:Archaea / Q000201:enzymology*; D003080:Cold Temperature; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism
chemical_list: D010088:Oxidoreductases; C412191:monophenolase; D014442:Monophenol Monooxygenase
keywords: 3,4-Dihydroxyphenylalanine (DOPA); Acidic cold-active tyrosinase; Co-expression; Cold-active tyrosinase; Marine archaea; Psychrophilic enzyme; Tyrosinase