A thermostable laccase from Streptomyces lavendulae REN-7: purification, characterization, nucleotide sequence, and expression.
We found a polyphenoloxidase (PPO) in the cell extract of Streptomyces lavendulae REN-7. About 0.8 mg of purified PPO was obtained from 200 g of the mycelia with a yield of 9.0%. REN-7-PPO showed broad substrate specificity toward various aromatic compounds. Moreover, this enzyme was capable of oxidation of syringaldazine, which is a specific substrate for laccase. Interestingly, REN-7-PPO retained its original activity after 20 min of incubation at even 70 degrees C. The gene encoding the PPO was cloned. Four copper-binding sites characteristics of laccases were contained in the deduced amino acid sequence. We constructed a high-level expression system of this gene in Escherichia coli. The properties of the recombinant enzyme were identical that of wild-type. In conclusion, this PPO is a thermostable laccase.
Suzuki
Takashi
T
Central Laboratory, Rengo Co., Ltd., Ohhiraki, Osaka, Japan.
Endo
Kohki
K
Ito
Masaaki
M
Tsujibo
Hiroshi
H
Miyamoto
Katsushiro
K
Inamori
Yoshihiko
Y
D001483:Base Sequence; D004156:Catechol Oxidase; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D006835:Hydrazones / Q000378:metabolism; D042845:Laccase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D013302:Streptomyces / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature
D006835:Hydrazones; C009370:syringaldazine; D004156:Catechol Oxidase; D042845:Laccase