scholarly journals The carbanion of nitroethane is an inhibitor of, and not a substrate for, flavocytochrome b2 [l-(+)-lactate dehydrogenase]

1990 ◽  
Vol 266 (1) ◽  
pp. 301-304 ◽  
Author(s):  
R Genet ◽  
F Lederer
Keyword(s):  
Electron Transfer ◽  
Amino Acid ◽  
Lactate Dehydrogenase ◽  
Active Site ◽  
Competitive Inhibitor ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
Flavocytochrome B2 ◽  
Enzyme Substrate

Although nitroethane does not bind to the active site of flavocytochrome b2, its anion, ethane nitronate, behaves as a competitive inhibitor, with a Ki of 2.2 mM. No electron transfer can be detected between the nitronate and the enzyme, in contrast with the observations of other workers on D-amino acid oxidase. Propionate is a competitive inhibitor, with a Ki of 28 mM. The significance of these results with respect to the proposed carbanion mechanism and the putative existence of a covalent enzyme-substrate intermediate is discussed.

P219L substitution in human D-amino acid oxidase impacts the ligand binding and catalytic efficiency

2020 ◽  
Vol 168 (5) ◽  
pp. 557-567
Author(s):  
Wanitcha Rachadech ◽  
Yusuke Kato ◽  
Rabab M Abou El-Magd ◽  
Yuji Shishido ◽  
Soo Hyeon Kim ◽  
...  
Keyword(s):  
Amino Acid ◽  
Conformational Changes ◽  
Active Site ◽  
Structural Changes ◽  
Catalytic Efficiency ◽  
Acid Oxidase ◽  
Wild Type ◽  
Amino Acid Oxidase ◽  
Adenine Ring ◽  
The Impact

Abstract Human D-amino acid oxidase (DAO) is a flavoenzyme that is implicated in neurodegenerative diseases. We investigated the impact of replacement of proline with leucine at Position 219 (P219L) in the active site lid of human DAO on the structural and enzymatic properties, because porcine DAO contains leucine at the corresponding position. The turnover numbers (kcat) of P219L were unchanged, but its Km values decreased compared with wild-type, leading to an increase in the catalytic efficiency (kcat/Km). Moreover, benzoate inhibits P219L with lower Ki value (0.7–0.9 µM) compared with wild-type (1.2–2.0 µM). Crystal structure of P219L in complex with flavin adenine dinucleotide (FAD) and benzoate at 2.25 Å resolution displayed conformational changes of the active site and lid. The distances between the H-bond-forming atoms of arginine 283 and benzoate and the relative position between the aromatic rings of tyrosine 224 and benzoate were changed in the P219L complex. Taken together, the P219L substitution leads to an increase in the catalytic efficiency and binding affinity for substrates/inhibitors due to these structural changes. Furthermore, an acetic acid was located near the adenine ring of FAD in the P219L complex. This study provides new insights into the structure–function relationship of human DAO.

Engineering the Substrate Specificity of Porcine Kidney d-Amino Acid Oxidase by Mutagenesis of the “Active-Site Lid”

2006 ◽  
Vol 139 (5) ◽  
pp. 873-879 ◽  
Author(s):  
Chiaki Setoyama ◽  
Yasuzo Nishina ◽  
Hisashi Mizutani ◽  
Ikuko Miyahara ◽  
Ken Hirotsu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Substrate Specificity ◽  
Active Site ◽  
Acid Oxidase ◽  
Porcine Kidney ◽  
Amino Acid Oxidase

scholarly journals Chemical mechanism of D-amino acid oxidase from Rhodotorula gracilis: pH dependence of kinetic parameters

1998 ◽  
Vol 330 (1) ◽  
pp. 311-314 ◽  
Author(s):  
F. RAMÓN ◽  
M. P. CASTILLÓN ◽  
I. DE LA MATA ◽  
C. ACEBAL
Keyword(s):  
Amino Acid ◽  
Kinetic Parameters ◽  
Ph Dependence ◽  
Competitive Inhibitor ◽  
Chemical Mechanism ◽  
Acid Oxidase ◽  
Protonation State ◽  
Amino Acid Oxidase ◽  
Basic Group ◽  
Rhodotorula Gracilis

The variation of kinetic parameters of D-amino acid oxidase from Rhodotorula gracilis with pH was used to gain information about the chemical mechanism of the oxidation of D-amino acids catalysed by this flavoenzyme. D-Alanine was the substrate used. The pH dependence of Vmax and Vmax/Km for alanine as substrate showed that a group with a pK value of 6.26-7.95 (pK1) must be unprotonated and a group with a pK of 10.8-9.90 (pK2) must be protonated for activity. The lower pK value corresponded to a group on the enzyme involved in catalysis and whose protonation state was not important for binding. The higher pK value was assumed to be the amino group of the substrate. Profiles of pKi for D-aspartate as competitive inhibitor showed that binding is prevented when a group on the enzyme with a pK value of 8.4 becomes unprotonated; this basic group was not detected in Vmax/Km profiles suggesting its involvement in binding of the β-carboxylic group of the inhibitor.

scholarly journals Synthesis and Biochemical Evaluation of Lid-Open D-Amino Acid Oxidase Inhibitors

Molecules ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 290
Author(s):  
Bence Szilágyi ◽  
Csilla Hargitai ◽  
Ádám A. Kelemen ◽  
Anita Rácz ◽  
György G. Ferenczy ◽  
...  
Keyword(s):  
Amino Acid ◽  
Physicochemical Properties ◽  
Active Site ◽  
Binding Pocket ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
New Class ◽  
Biochemical Evaluation ◽  
Low Sensitivity ◽  
Adme Profile

Most of the known inhibitors of D-amino acid oxidase (DAAO) are small polar molecules recognized by the active site of the enzyme. More recently a new class of DAAO inhibitors has been disclosed that interacts with loop 218−224 at the top of the binding pocket. These compounds have a significantly larger size and more beneficial physicochemical properties than most reported DAAO inhibitors, however, their structure-activity relationship is poorly explored. Here we report the synthesis and evaluation of this type of DAAO inhibitors that open the lid over the active site of DAAO. In order to collect relevant SAR data we varied two distinct parts of the inhibitors. A systematic variation of the pendant aromatic substituents according to the Topliss scheme resulted in DAAO inhibitors with low nanomolar activity. The activity showed low sensitivity to the substituents investigated. The variation of the linker connecting the pendant aromatic moiety and the acidic headgroup revealed that the interactions of the linker with the enzyme were crucial for achieving significant inhibitory activity. Structures and activities were analyzed based on available X-ray structures of the complexes. Our findings might support the design of drug-like DAAO inhibitors with advantageous physicochemical properties and ADME profile.

scholarly journals OPHIDIAN l-AMINO ACID OXIDASE. THE NATURE OF THE ENZYME-SUBSTRATE COMPLEXES

1965 ◽  
Vol 95 (1) ◽  
pp. 262-269 ◽  
Author(s):  
EA ZELLER ◽  
G RAMACHANDER ◽  
GA FLEISHER ◽  
T ISHIMARU ◽  
V ZELLER
Keyword(s):  
Amino Acid ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
Enzyme Substrate

Ultrafast photoinduced electron transfer in o-aminobenzoate – D-amino acid oxidase complex

2021 ◽  
pp. 113448
Author(s):  
Seiji Taniguchi ◽  
Haik Chosrowjan ◽  
Haruhiko Tamaoki ◽  
Yasuzo Nishina ◽  
Arthit Nueangaudom ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Amino Acid ◽  
Photoinduced Electron Transfer ◽  
Acid Oxidase ◽  
Amino Acid Oxidase

scholarly journals The mechanism of action of serine transhydroxymethylase

1970 ◽  
Vol 116 (2) ◽  
pp. 277-286 ◽  
Author(s):  
P. M. Jordan ◽  
M. Akhtar
Keyword(s):  
Schiff Base ◽  
Amino Acid ◽  
Hydrogen Atom ◽  
Mechanism Of Action ◽  
Active Site ◽  
Enzyme Preparation ◽  
Pyridoxal Phosphate ◽  
Acid Oxidase ◽  
Amino Acid Oxidase

1. The preparation of stereospecifically tritiated glycines and the determination of their absolute configurations by the use of d-amino acid oxidase are described. 2. The reaction catalysed by serine transhydroxymethylase, which results in the conversion of glycine into serine, has been separated into at least four partial reactions. It is suggested that the first event in this conversion is the formation of a Schiff base intermediate of glycine and pyridoxal phosphate. The next important step involves the removal of the 2S-hydrogen atom of glycine to give a carbanion intermediate. Experiments pertinent to the mechanism of conversion of this carbanion intermediate into serine are described. 3. The enzyme preparation catalysing the conversion of glycine into serine also participates in the conversion of glycine into threonine and allothreonine. In both these conversions, glycine → serine and glycine → threonine, the 2S-hydrogen atom of glycine is eliminated and the 2R-hydrogen atom of glycine is retained. 4. In the light of these experiments the mechanism of action of serine transhydroxymethylase is discussed. It is suggested that methylenetetrahydrofolate is the carrier of formaldehyde, from which formaldehyde may be liberated at the active site of the enzyme, thus allowing the overall reaction to take place.

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