Isolation and characterization of novel tyrosinase from Laceyella sacchari

Protein Pept Lett. 2012 May;19(5):538-43. doi: 10.2174/092986612800191035.

Abstract

We here describe the isolation and characterization of a tyrosinase from a newly isolated soil bacterium. 16S rDNA sequence analysis revealed that the bacterium most probably belongs to the species Laceyella sacchari (Ls) ( > 99.9 % identity). The tyrosinase extracellular enzymatic activity was induced in the presence of L-methionine and CuSO4. The crude enzyme was first purified by centrifugation followed by ammonium sulphate precipitation and ultrafiltration. After removal of a brown pigment, probably melanin, a purified enzyme was obtained by further separation of the crude protein mixture using size exclusion chromatography. Some 10.5 mg of pure tyrosinase (LsTyr) was isolated with a molecular mass of 30 910 Da, based on MALDI mass spectrometry. Together with the observed enzymatic activity, N-terminal chemical sequence analysis confirmed that the isolated enzyme is homologous to other tyrosinases. The kinetic parameters for the diphenol substrates L-DOPA and dopamine and for the monophenol substrate L-tyrosine were determined to be KM = 4.5 mM , 1.5 mM and 0.055 mM, and kcat/KM = 261.5 mM-1 s -1 , 30.6 mM-1 s-1 and 56.3 mM-1 s-1, respectively. Maximal activities of the purified enzyme were found to occur at pH 6.8.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillales / enzymology*
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / isolation & purification*
  • Bacterial Proteins / metabolism
  • Base Sequence
  • DNA, Bacterial / genetics
  • Dopamine / metabolism
  • Enzyme Stability
  • Hydrogen-Ion Concentration
  • Kinetics
  • Levodopa / metabolism
  • Molecular Sequence Data
  • Monophenol Monooxygenase / chemistry*
  • Monophenol Monooxygenase / genetics
  • Monophenol Monooxygenase / isolation & purification*
  • Monophenol Monooxygenase / metabolism
  • RNA, Ribosomal, 16S / genetics
  • Sequence Alignment
  • Tyrosine / metabolism

Substances

  • Bacterial Proteins
  • DNA, Bacterial
  • RNA, Ribosomal, 16S
  • Tyrosine
  • Levodopa
  • Monophenol Monooxygenase
  • Dopamine