1783-96-6Relevant articles and documents
Biochemical characterization of an extremely thermostable l-asparaginase from Thermococcus gammatolerans EJ3
Zuo, Shaohua,Xue, Dong,Zhang, Tao,Jiang, Bo,Mu, Wanmeng
, p. 122 - 129 (2014)
Microbial l-asparaginases which catalyze the conversion of l-asparagine to l-asparate and ammonia, have been proved to be useful in medical and food industries. In the present work, a thermostable l-asparaginase was characterized from a hyperthermophilic archaeon strain, Thermococcus gammatolerans EJ3. Cloning and recombinant expression of Tco. gammatolerans l-asparaginase was performed in Escherichia coli. The recombinant enzyme was purified to homogeneity by nickel-affinity chromatography, and was characterized as a homodimer composed of two identical subunits of approximately 36.5 kDa. The optimum pH and temperature were 8.5 and 85 °C, respectively. The purified enzyme had specific activities of 7622 and 2926 U mg-1for l-asparagine and l-glutamine, respectively, and exhibited promising thermostability at all tested temperatures from 70 to 95 °C. In addition, it displayed very high catalytic efficiency toward substrate l-asparagine. The Michaelis-Menten constant (Km), turnover number (kcat), and catalytic efficiency (kcat/Km) values for substrate l-asparagine were estimated to be 10.0 mM, 5721 s-1, and 572.1 mM-1s-1, respectively.
Structure, mechanism, and substrate profile for Sco3058: The closest bacterial homologue to human renal dipeptidase
Cummings, Jennifer A.,Nguyen, Tinh T.,Fedorov, Alexander A.,Kolb, Peter,Xu, Chengfu,Fedorov, Elena V.,Shoichet, Brian K.,Barondeau, David P.,Almo, Steven C.,Raushel, Frank M.
, p. 611 - 622 (2010)
Human renal dipeptidase, an enzyme associated with glutathione metabolism and the hydrolysis of β-lactams, is similar in sequence to a cluster of ～400 microbial proteins currently annotated as nonspecific dipeptidases within the amidohydrolase superfamily. The closest homologue to the human renal dipeptidase from a fully sequenced microbe is Sco3058 from Streptomyces coelicolor. Dipeptide substrates of Sco3058 were identified by screening a comprehensive series of L-Xaa-L-Xaa, L-Xaa-D-Xaa, and D-Xaa-L-Xaa dipeptide libraries. The substrate specificity profile shows that Sco3058 hydrolyzes a broad range of dipeptides with a marked preference for an L-amino acid at the N-terminus and a D-amino acid at the C-terminus. The best substrate identified was L-Arg-D-Asp (kcat/Km = 7.6 x 105 M -1 s-1). The three-dimensional structure of Sco3058 was determined in the absence and presence of the inhibitors citrate and a phosphinate mimic of L-Ala-D-Asp. The enzyme folds as a (β/α)8 barrel, and two zinc ions are bound in the active site. Site-directed mutagenesis was used to probe the importance of specific residues that have direct interactions with the substrate analogues in the active site (Asp-22, His-150, Arg-223, and Asp-320). The solvent viscosity and kinetic effects of D2O indicate that substrate binding is relatively sticky and that proton transfers do not occurr during the rate-limiting step. A bell-shaped pH-rate profile for kcat and kcat/Km indicated that one group needs to be deprotonated and a second group must be protonated for optimal turnover. Computational docking of high-energy intermediate forms of L/D-Ala-L/D-Ala to the three-dimensional structure of Sco3058 identified the structural determinants for the stereochemical preferences for substrate binding and turnover.
Propagation of biochirality: Crossovers and nonclassical crystallization kinetics of aspartic acid in water
Lee, Tu,Lin, Yu Kun,Tsai, Ya Chung,Lee, Hung Lin
, p. 768 - 779 (2013)
All experimental procedures discussed could be treated as a screening tool for probing the existence of molecular association among the chiral molecules and the solvent system. The molecular association phases of a racemic conglomerate solution (CS) and a
AN AGE DETERMINATION OF AN ANCIENT BURIAL MOUND MAN BY APPARENT RACEMIZATION REACTION OF ASPERTIC ACID IN TOOTH DENTIN
Shimoyama, Akira,Harada, Kaoru
, p. 1661 - 1664 (1984)
An age of a man from an ancient burial mound dated to the seventh century was estimated to be about 50 years old, using an apparent racemizatiopn phenomenon of aspartic acid found from the tooth dentin.For this estimate, the D/L ratios of modern teeth and
Structural and functional analysis of pantocin A: An antibiotic from Pantoea agglomerans discovered by heterologous expression of cloned genes
Jin, Mi,Liu, Liang,Wright, Sandra A. I.,Beer, Steven V.,Clardy, Jon
, p. 2898 - 2901 (2003)
Small-molecule chemistry and biochemical techniques have been used to determine the structure and mode of function of pantocin A (see structure), a naturally occurring antibiotic. Pantocin A functions as an inhibitor of histidine biosynthesis, as shown by its ability to inhibit the action of L-histidinol phosphate aminotransferase, which converts imidazole acetol phosphate to L-histidinol phosphate in Escherichia coli.
Evidence of the hypsithermal verified using the racemization rate constant of amino acids: An estimation of paleo-ground temperatures
Takano, Yoshinori,Kudo, Junya,Kaneko, Takeo,Kobayashi, Kensei,Ishikawa, Yoji,Marumo, Katsumi
, p. 1029 - 1030 (2004)
The kinetics of a racemization reaction for aspartic acid in boreal terrestrial sediment core samples was investigated in detail to determine the rate constant (kASP) and the difference of the paleo-ground temperatures. The Arrhenius plot betwe
Optical Resolution of Aspartic Acid by Using Copper Complexes of Optically Active Amino Acids
Harada, Kaoru,Fujii, Noriko
, p. 653 - 654 (1983)
DL-Aspartic acid was resolved with high optical purity in the presence of an optically active amino acid copper complex.The mechanism of the optical resolution was explained by the competitive inhibition of crystallization.
Racemization of the aspartic acid residue of amyloid-β peptide by a radical reaction
Tambo, Koharu,Yamaguchi, Tomomi,Kobayashi, Keiko,Terauchi, Eri,Ichi, Ikuyo,Kojo, Shosuke
, p. 416 - 418 (2013)
Human amyloid-β peptide 1-42 (Aβ) was subjected to a radical reaction by using ascorbic acid and CuCl2. The percentage of D-aspartic acid (D-Asp) after 24 h had increased to 6.69 ± 0.09%, this being comparable with the reported D-Asp concentration of purified core amyloids in Alzheimer's disease patients. This racemization was significantly inhibited by radical scavengers. L-Alanine was also racemized during the same reaction.
Switchable Chiral Selection of Aspartic Acids by Dynamic States of Brushite
Jiang, Wenge,Pan, Haihua,Zhang, Zhisen,Qiu, S. Roger,Kim, J. Dongun,Xu, Xurong,Tang, Ruikang
, p. 8562 - 8569 (2017)
We herein show the chiral recognition and separation of aspartic acid (Asp) enantiomers by achiral brushite due to the asymmetries of their dynamical steps in its nonequilibrium states. Growing brushite has a higher adsorption affinity to d-Asp, while l-A
Immobilization of L-aspartate oxidase from Sulfolobus tokodaii as a biocatalyst for resolution of aspartate solutions
D'Arrigo, Paola,Allegretti, Chiara,Fiorati, Andrea,Piubelli, Luciano,Rosini, Elena,Tessaro, Davide,Valentino, Mattia,Pollegioni, Loredano
, p. 1106 - 1114 (2015)
L-Aspartate oxidase from the thermophilic archaebacterium Sulfolobus tokodaii (StLASPO) catalyzes the stereoselective oxidative deamination of L-aspartate to yield oxaloacetate, ammonia and hydrogen peroxide. The recombinant flavoenzyme shows distinctive
