scholarly journals Functionalized Bilayer Membranes as Artificial Tryptophan Synthase. Characterization of Catalytic Efficiency, Substrate Specificity, and Reaction Selectivity

1990 ◽  
Vol 63 (8) ◽  
pp. 2339-2345 ◽  
Author(s):  
Yukito Murakami ◽  
Jun-ichi Kikuchi ◽  
Yoshio Hisaeda ◽  
Koichiro Nakamura ◽  
Tomoyuki Kitazaki ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Catalytic Efficiency ◽  
Tryptophan Synthase ◽  
Bilayer Membranes ◽  
Reaction Selectivity

scholarly journals Kinetic characterization of yeast alcohol dehydrogenases. Amino acid residue 294 and substrate specificity.

1987 ◽  
Vol 262 (8) ◽  
pp. 3754-3761
Author(s):  
A.J. Ganzhorn ◽  
D.W. Green ◽  
A.D. Hershey ◽  
R.M. Gould ◽  
B.V. Plapp
Keyword(s):  
Amino Acid ◽  
Substrate Specificity ◽  
Amino Acid Residue ◽  
Kinetic Characterization ◽  
Alcohol Dehydrogenases

scholarly journals An Electrochemical Approach to Follow and Evaluate the Kinetic Catalysis of Ricin on hsDNA

Life ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 405
Author(s):  
George Oliveira ◽  
José Maurício Schneedorf
Keyword(s):  
Catalytic Efficiency ◽  
Ricin Toxin ◽  
Wave Voltammetry ◽  
Progress Curve ◽  
Electrochemical Approach ◽  
Electro Oxidation ◽  
Castor Seeds ◽  
Identification And Characterization ◽  
Medical Countermeasures

International authorities classify the ricin toxin, present in castor seeds, as a potential agent for use in bioterrorism. Therefore, the detection, identification, and characterization of ricin are considered the first actions for its risk assessment during a suspected exposure, parallel to the development of therapeutic and medical countermeasures. In this study, we report the kinetic analysis of electro-oxidation of adenine released from hsDNA by the catalytic action of ricin by square wave voltammetry. The results suggest that ricin-mediated adenine release exhibited an unusual kinetic profile, with a progress curve controlled by the accumulation of the product and the values of the kinetic constants of 46.6 µM for Km and 2000 min−1 for kcat, leading to a catalytic efficiency of 7.1 × 105 s−1 M−1.

Characterization of a novel moderate-substrate specificity amino acid racemase from the hyperthermophilic archaeon Thermococcus litoralis

2021 ◽  
Author(s):  
Ryushi Kawakami ◽  
Chinatsu Kinoshita ◽  
Tomoki Kawase ◽  
Mikio Sato ◽  
Junji Hayashi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Substrate Specificity ◽  
Enzyme Stability ◽  
Hyperthermophilic Archaea ◽  
Thermococcus Litoralis ◽  
Hyperthermophilic Archaeon ◽  
Aminobutyrate Aminotransferase ◽  
Chaperone Protein ◽  
Amino Acid Racemase

Abstract The amino acid sequence of the OCC_10945 gene product from the hyperthermophilic archaeon Thermococcus litoralis DSM5473, originally annotated as γ-aminobutyrate aminotransferase, is highly similar to that of the uncharacterized pyridoxal 5ʹ-phosphate (PLP)-dependent amino acid racemase from Pyrococcus horikoshii. The OCC_10945 enzyme was successfully overexpressed in Escherichia coli by co-expression with a chaperone protein. The purified enzyme demonstrated PLP-dependent amino acid racemase activity primarily toward Met and Leu. Although PLP contributed to enzyme stability, it only loosely bound to this enzyme. Enzyme activity was strongly inhibited by several metal ions, including Co2+ and Zn2+, and non-substrate amino acids such as l-Arg and l-Lys. These results suggest that the underlying PLP-binding and substrate recognition mechanisms in this enzyme are significantly different from those of the other archaeal and bacterial amino acid racemases. This is the first description of a novel PLP-dependent amino acid racemase with moderate substrate specificity in hyperthermophilic archaea.

scholarly journals Human cytotoxic lymphocyte tryptase. Its purification from granules and the characterization of inhibitor and substrate specificity.

1988 ◽  
Vol 263 (26) ◽  
pp. 13215-13222 ◽  
Author(s):  
M Poe ◽  
C D Bennett ◽  
W E Biddison ◽  
J T Blake ◽  
G P Norton ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Cytotoxic Lymphocyte

scholarly journals Characterization of the putative tryptophan synthase β-subunit from Mycobacterium tuberculosis

2009 ◽  
Vol 41 (5) ◽  
pp. 379-388 ◽  
Author(s):  
Hongbo Shen ◽  
Yanping Yang ◽  
Feifei Wang ◽  
Ying Zhang ◽  
Naihao Ye ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Tryptophan Synthase ◽  
Β Subunit
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