Analysis of the Substrate Specificity of Human Sulfotransferases SULT1A1 and SULT1A3:  Site-Directed Mutagenesis and Kinetic Studies†

Biochemistry ◽  
1999 ◽  
Vol 38 (32) ◽  
pp. 10474-10479 ◽  
Author(s):  
Lulu A. Brix ◽  
Amanda C. Barnett ◽  
Ronald G. Duggleby ◽  
Barbara Leggett ◽  
Michael E. McManus
Keyword(s):  
Substrate Specificity ◽  
Kinetic Studies ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis

scholarly journals Study of substrate specificity of human aromatase by site directed mutagenesis

2002 ◽  
Vol 269 (5) ◽  
pp. 1393-1405 ◽  
Author(s):  
P. Auvray ◽  
C. Nativelle ◽  
R. Bureau ◽  
P. Dallemagne ◽  
G.-E. Séralini ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Human Aromatase

Probing the Role of Tyr 64 ofTreponema denticolaCystalysin by Site-Directed Mutagenesis and Kinetic Studies†

Biochemistry ◽  
2005 ◽  
Vol 44 (42) ◽  
pp. 13970-13980 ◽  
Author(s):  
Barbara Cellini ◽  
Mariarita Bertoldi ◽  
Riccardo Montioli ◽  
Carla Borri Voltattorni
Keyword(s):  
Kinetic Studies ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis

scholarly journals Versatile Fungal Polyphenol Oxidase with Chlorophenol Bioremediation Potential: Characterization and Protein Engineering

2018 ◽  
Vol 84 (23) ◽  
Author(s):  
Efstratios Nikolaivits ◽  
Maria Dimarogona ◽  
Ioanna Karagiannaki ◽  
Angelina Chalima ◽  
Ayelet Fishman ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Fruits And Vegetables ◽  
Homology Model ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Gene Encoding ◽  
Content Type ◽  
Polyphenol Oxidases ◽  
Increased Activity ◽  
Work Knowledge

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.

scholarly journals Enhanced Activity and Substrate Specificity by Site‐Directed Mutagenesis for the P450 119 Peroxygenase Catalyzed Sulfoxidation of Thioanisole

ChemistryOpen ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 1076-1083
Author(s):  
Xiaoyao Wei ◽  
Chun Zhang ◽  
Xiaowei Gao ◽  
Yanping Gao ◽  
Ya Yang ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Enhanced Activity
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