scholarly journals Catalytic Activities of Salicylaldehyde Derivatives. I. Catalytic Effects of 4-Formyl-3-hydroxyphenyltrimethylammonium Bromide on the Racemization of L-Amino Acid

1969 ◽  
Vol 42 (9) ◽  
pp. 2624-2627 ◽  
Author(s):  
Makoto Ando ◽  
Sakae Emoto
Keyword(s):  
Amino Acid ◽  
Catalytic Activities ◽  
Salicylaldehyde Derivatives ◽  
Catalytic Effects

Micellar Catalytic Effects on the Kinetics of the Ionization of Basic Amino Acid and Acidic Amino Acid Studied by the Ultrasonic Absorption Method

Langmuir ◽  
1995 ◽  
Vol 11 (5) ◽  
pp. 1477-1481
Author(s):  
Teruyo Yamashita ◽  
Miyuki Yamasaki ◽  
Takayuki Sano ◽  
Shoji Harada ◽  
Hiroshige Yano
Keyword(s):  
Amino Acid ◽  
Basic Amino Acid ◽  
Ultrasonic Absorption ◽  
Absorption Method ◽  
Acidic Amino Acid ◽  
Kinetics Of ◽  
Catalytic Effects

scholarly journals Isolation of four forms of acetone-induced cytochrome P-450 in chicken liver by h.p.l.c. and their enzymic characterization

1990 ◽  
Vol 269 (1) ◽  
pp. 85-91 ◽  
Author(s):  
J F Sinclair ◽  
S Wood ◽  
L Lambrecht ◽  
N Gorman ◽  
L Mende-Mueller ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Exchange Chromatography ◽  
Amino Acid Sequences ◽  
Chicken Liver ◽  
Terminal Amino Acid ◽  
Catalytic Activities ◽  
Terminal Amino ◽  
Cytochrome P 450 ◽  
Terminal Amino Acid Sequence

The purpose of this study was to purify and characterize the forms of cytochrome P-450 induced in chicken liver by acetone or ethanol. Using high performance liquid ion-exchange chromatography, we were able to isolate at least four different forms of cytochrome P-450 which were induced by acetone in chicken liver. All four forms of cytochrome P-450 proved to be distinct proteins, as indicated by their N-terminal amino acid sequences and their reconstituted catalytic activities. Two of these forms, also induced by glutethimide in chicken embryo liver, appeared to be cytochromes P450IIH1 and P450IIH2. Both of these cytochromes P-450 have identical catalytic activities towards benzphetamine demethylation. However, they differ in their abilities to hydroxylate p-nitrophenol and to convert acetaminophen into a metabolite that forms a covalent adduct with glutathione at the 3-position. Another form of cytochrome P-450 induced by acetone is highly active in the hydroxylation of p-nitrophenol and in the conversion of acetaminophen to a reactive metabolite, similar to reactions catalysed by mammalian cytochrome P450IIE. Yet the N-terminal amino acid sequence of this form has only 30-33% similarity with cytochrome P450IIE purified from rat, rabbit and human livers. A fourth form of cytochrome P-450 was identified whose N-terminal amino acid sequence and enzymic activities do not correspond to any mammalian cytochromes P-450 reported to be induced by acetone or ethanol.

scholarly journals Facilitating the Evolution of Esterase Activity from a Promiscuous Enzyme (Mhg) with Catalytic Functions of Amide Hydrolysis and Carboxylic Acid Perhydrolysis by Engineering the Substrate Entrance Tunnel

2016 ◽  
Vol 82 (22) ◽  
pp. 6748-6756 ◽  
Author(s):  
Xiaodan Yan ◽  
Jianjun Wang ◽  
Yu Sun ◽  
Junge Zhu ◽  
Sheng Wu
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Engineering ◽  
Esterase Activity ◽  
Molecular Basis ◽  
Catalytic Triad ◽  
Amino Acid Substitutions ◽  
Biological Functions ◽  
Catalytic Activities ◽  
Efficient Strategy

ABSTRACTPromiscuous enzymes are generally considered to be starting points in the evolution of offspring enzymes with more specific or even novel catalytic activities, which is the molecular basis of producing new biological functions. Mhg, a typical α/β fold hydrolase, was previously reported to have both γ-lactamase and perhydrolase activities. However, despite having high structural similarity to and sharing an identical catalytic triad with an extensively studied esterase fromPseudomonas fluorescens, this enzyme did not show any esterase activity. Molecular docking and sequence analysis suggested a possible role for the entry of the binding pocket in blocking the entrance tunnel, preventing the ester compounds from entering into the pocket. By engineering the entrance tunnel with only one or two amino acid substitutions, we successfully obtained five esterase variants of Mhg. The variants exhibited a very broad substrate acceptance, hydrolyzing not only the classicalp-nitrophenol esters but also various types of chiral esters, which are widely used as drug intermediates. Site 233 at the entrance tunnel of Mhg was found to play a pivotal role in modulating the three catalytic activities by adjusting the size and shape of the tunnel, with different amino acid substitutions at this site facilitating different activities. Remarkably, the variant with the L233G mutation was a very specific esterase without any γ-lactamase and perhydrolase activities. Considering the amino acid conservation and differentiation, this site could be a key target for future protein engineering. In addition, we demonstrate that engineering the entrance tunnel is an efficient strategy to regulate enzyme catalytic capabilities.IMPORTANCEPromiscuous enzymes can act as starting points in the evolution of novel catalytic activities, thus providing a molecular basis for the production of new biological functions. In this study, we identified a critical amino acid residue (Leu233) at the entry of the substrate tunnel of a promiscuous enzyme, Mhg. We found that substitution of this residue with smaller amino acids such as Gly, Ala, Ser, or Pro endowed the enzyme with novel esterase activity. Different amino acids at this site can facilitate different catalytic activities. These findings exhibited universal significance in this subset of α/β fold hydrolases, including Mhg. Furthermore, we demonstrate that engineering the entrance tunnel is an efficient strategy to evolve new enzyme catalytic capabilities. Our study has important implications for the regulation of enzyme catalytic promiscuity and development of protein engineering methodologies.

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