An evaluation of the substrate specificity, and of its modification by site-directed mutagenesis, of the cloned L-lactate dehydrogenase from Bacillus stearothermophilus

1989 ◽  
Vol 111 (17) ◽  
pp. 6800-6804 ◽  
Author(s):  
Marcel A. Luyten ◽  
Daniel Bur ◽  
Hla Wynn ◽  
Wendy Parris ◽  
Marvin Gold ◽  
...  
1987 ◽  
Vol 15 (1) ◽  
pp. 152-153 ◽  
Author(s):  
ANTHONY R. CLARKE ◽  
DALE B. WIGLEY ◽  
DAVID A. BARSTOW ◽  
WILLIAM N. CHIA ◽  
ADAM D. B. WALDMAN ◽  
...  

2002 ◽  
Vol 269 (5) ◽  
pp. 1393-1405 ◽  
Author(s):  
P. Auvray ◽  
C. Nativelle ◽  
R. Bureau ◽  
P. Dallemagne ◽  
G.-E. Séralini ◽  
...  

1990 ◽  
Vol 107 (2) ◽  
pp. 267-272 ◽  
Author(s):  
Mauno Vihinen ◽  
Pauli Olikka ◽  
Jukka Niskanen ◽  
Peter Meyer ◽  
IIari Suominen ◽  
...  

2018 ◽  
Vol 84 (23) ◽  
Author(s):  
Efstratios Nikolaivits ◽  
Maria Dimarogona ◽  
Ioanna Karagiannaki ◽  
Angelina Chalima ◽  
Ayelet Fishman ◽  
...  

ABSTRACTPolyphenol oxidases (PPOs) have been mostly associated with the undesirable postharvest browning in fruits and vegetables and have implications in human melanogenesis. Nonetheless, they are considered useful biocatalysts in the food, pharmaceutical, and cosmetic industries. The aim of the present work was to characterize a novel PPO and explore its potential as a bioremediation agent. A gene encoding an extracellular tyrosinase-like enzyme was amplified from the genome ofThermothelomyces thermophilaand expressed inPichia pastoris. The recombinant enzyme (TtPPO) was purified and biochemically characterized. Its production reached 40 mg/liter, and it appeared to be a glycosylated and N-terminally processed protein.TtPPO showed broad substrate specificity, as it could oxidize 28/30 compounds tested, including polyphenols, substituted phenols, catechols, and methoxyphenols. Its optimum temperature was 65°C, with a half-life of 18.3 h at 50°C, while its optimum pH was 7.5. The homology model ofTtPPO was constructed, and site-directed mutagenesis was performed in order to increase its activity on mono- and dichlorophenols (di-CPs). The G292N/Y296V variant ofTtPPO 5.3-fold increased activity on 3,5-dichlorophenol (3,5-diCP) compared to the wild type.IMPORTANCEA novel fungal PPO was heterologously expressed and biochemically characterized. Construction of single and double mutants led to the generation of variants with altered specificity against CPs. Through this work, knowledge is gained regarding the effect of mutations on the substrate specificity of PPOs. This work also demonstrates that more potent biocatalysts for the bioremediation of harmful CPs can be developed by applying site-directed mutagenesis.


ChemistryOpen ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 1076-1083
Author(s):  
Xiaoyao Wei ◽  
Chun Zhang ◽  
Xiaowei Gao ◽  
Yanping Gao ◽  
Ya Yang ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document