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Isolation and Characterization of Novel Tyrosinase from Laceyella sacchari

[ Vol. 19 , Issue. 5 ]


Aleksandar Dolashki, Wolfgang Voelter, Adriana Gushterova, Jozef Van Beeumen, Bart Devreese and Bozhidar Tchorbanov   Pages 538 - 543 ( 6 )


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.


Tyrosinase, Laceyella sacchari, MS, MALDI


Academy G. Bonchev Street, bl. 9, 1113 Sofia, Bulgaria.

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