We purified D-amino acid oxidase (EC 1.4.3.3, DAO) from Xenopus laevis tadpoles. The optimal temperature and pH for enzyme activity were 35-40 °C and 8.3-9.0, respectively, depending on the substrate amino acids available to the enzyme; the highest activity was observed with D-proline followed by D-phenylalanine. Activity was significantly inhibited by p-hydroxymercuribenzoate, but only moderately by p-chloromercuribenzoate or benzoate. Enzyme activity was increased until the final tadpole stage, but was reduced to one-third in the adult and was localized primarily in the kidney. The tadpoles contained high concentrations of D-proline close to the final developmental stage and nearly no D-amino acids were detected in the adult frog, indicating that D-amino acid oxidase functions in metamorphosis.
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http://dx.doi.org/10.1016/j.cbpb.2013.08.004 | DOI Listing |
Front Microbiol
January 2025
Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China.
Background: d-Tryptophan is recognised for its unique physiological properties. In this study, we aimed to explore the dynamic trends and emerging topics in d-tryptophan research to offer fresh perspectives for future studies.
Methods: Employing bibliometric analysis, we examined the literature on d-tryptophan indexed in the Web of Science Core Collection from January 1987 to December 2023.
ACS Omega
January 2025
Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan.
Various symmetric and asymmetric imines were synthesized using the novel amine oxidase, obtained as variants of d-amino acid oxidase (pkDAO) from porcine kidney (Y228L/R283G) and (I230A/R283G). Active primary imines produced as intermediates in the oxidation of methylbenzylamine (MBA) derivatives were trapped by aliphatic, aromatic amines and diamines as nucleophiles forming new imines. ()-Fluoro-MBA was the best substrate for symmetric imine synthesis, providing almost stoichiometric conversion (100 mM) and achieving nearly 100% yield.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States.
Visible light-driven pyridoxal radical biocatalysis has emerged as a new strategy for the stereoselective synthesis of valuable noncanonical amino acids in a protecting-group-free fashion. In our previously developed dehydroxylative C-C coupling using engineered PLP-dependent tryptophan synthases, an enzyme-controlled unusual α-stereochemistry reversal and pH-controlled enantiopreference were observed. Herein, through high-throughput photobiocatalysis, we evolved a set of stereochemically complementary PLP radical enzymes, allowing the synthesis of both l- and d-amino acids with enhanced enantiocontrol across a broad pH window.
View Article and Find Full Text PDFFront Microbiol
January 2025
Shanghai Engineering Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai, China.
Strain LCG007, isolated from Lu Chao Harbor's intertidal water, phylogenetically represents a novel genus within the family Rhodobacteraceae. Metabolically, it possesses a wide array of amino acid metabolic genes that enable it to thrive on both amino acids or peptides. Also, it could hydrolyze peptides containing D-amino acids, highlighting its potential role in the cycling of refractory organic matter.
View Article and Find Full Text PDFMacromol Rapid Commun
January 2025
State Key Laboratory of Applied Organic Chemistry, Lanzhou Magnetic Resonance Center, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, China.
Residual dipolar coupling (RDC) not only contributes to the dynamic analysis of proteins but also provides a robust route for the structure determination of small organic compounds. An essential prerequisite for this methodology is the availability of alignment media. Herein, a series of novel peptide-based alignment media are generated by introducing D-type or halogen-bearing amino acids for RDC measurements.
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