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.

Use of inhibitors to study reactions catalyzed by enzymes requiring pyridoxal phosphate as coenzyme

2000 ◽  
Vol 72 (3) ◽  
pp. 373-384 ◽  
Author(s):  
Benjamin Adams ◽  
B. Svante Axelsson ◽  
Kenneth J. M. Beresford ◽  
Nicola J. Church ◽  
Philip A. Spencer ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Active Site ◽  
Aspartate Aminotransferase ◽  
Pyridoxal Phosphate ◽  
Family Formation ◽  
Enzyme Inhibitors ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
Naturally Occurring

The stereochemistry of a variety of pyridoxal phosphate-mediated enzymic reactions has been studied using enzyme inhibitors that are stereospecifically labeled in the β-position with deuterium. A versatile synthesis has been developed to prepare a wide variety of stereospecifically labeled d- and l-amino acids and inhibitors. Investigation of the "turnover" of β-chloro-d-alanine and d- and l-serine-O-sulfate by d-amino acid aminotransferase and l-aspartate aminotransferase respectively has shown that reaction within the active site of the former enzyme occurs with retention of stereochemistry. Although l-aspartate aminotransferase is an enzyme of the α-family, when it was incubated with β-chloro-l-alanine in the presence of 2-mercaptoethanol, β-substitution occurred. This was shown to involve retention of stereochemistry, an outcome typical of reactions catalyzed by enzymes of the β-family that have little or no homology with enzymes of the α-family. Formation of the "Schnackerz intermediate" has been studied as has the d-amino acid oxidase catalyzed reaction of the naturally occurring inhibitor d-propargylglycine.

Impairment of Platelet Aggregation by Echis colorata Venom Mediated by L-Amino Acid Oxidase or H2O2

1982 ◽  
Vol 48 (03) ◽  
pp. 277-282 ◽  
Author(s):  
I Nathan ◽  
A Dvilansky ◽  
T Yirmiyahu ◽  
M Aharon ◽  
A Livne
Keyword(s):  
Hydrogen Peroxide ◽  
Amino Acid ◽  
Platelet Aggregation ◽  
Snake Venom ◽  
Oxidase Activity ◽  
Enzyme Preparation ◽  
Acid Oxidase ◽  
Crude Venom ◽  
Amino Acid Oxidase ◽  
Hemostatic Disorders

SummaryEchis colorata bites cause impairment of platelet aggregation and hemostatic disorders. The mechanism by which the snake venom inhibits platelet aggregation was studied. Upon fractionation, aggregation impairment activity and L-amino acid oxidase activity were similarly separated from the crude venom, unlike other venom enzymes. Preparations of L-amino acid oxidase from E.colorata and from Crotalus adamanteus replaced effectively the crude E.colorata venom in impairment of platelet aggregation. Furthermore, different treatments known to inhibit L-amino acid oxidase reduced in parallel the oxidase activity and the impairment potency of both the venom and the enzyme preparation. H2O2 mimicked characteristically the impairment effects of L-amino acid oxidase and the venom. Catalase completely abolished the impairment effects of the enzyme and the venom. It is concluded that hydrogen peroxide formed by the venom L-amino acid oxidase plays a role in affecting platelet aggregation and thus could contribute to the extended bleeding typical to persons bitten by E.colorata.

scholarly journals Studies on the Mechanism of Action of d-Amino Acid Oxidase

1971 ◽  
Vol 246 (22) ◽  
pp. 6855-6866 ◽  
Author(s):  
Christopher T. Walsh ◽  
Agnes Schonbrunn ◽  
Robert H. Abeles
Keyword(s):  
Amino Acid ◽  
Mechanism Of Action ◽  
Acid Oxidase ◽  
Amino Acid Oxidase

An Automated Detection System for Most L-α-Amino Acids

1969 ◽  
Vol 15 (2) ◽  
pp. 154-161 ◽  
Author(s):  
K Van Dyke ◽  
C Szustkiewicz
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Detection System ◽  
Automated System ◽  
Acid Oxidase ◽  
Enzymatic Reactions ◽  
Amino Acid Oxidase ◽  
Automated Method ◽  
Wide Range

Abstract An automated system for the determination of the L-α form of the majority of amino acids is presented. The method is based upon oxidative deamination of the amino acid coupled with oxidation of o-dianisidine by hydrogen peroxide. This procedure can be used comparatively for the determination of a mixture of L-α-amino acids or for the majority of separated L-α-amino acids (especially in conjunction with column separations from urine and blood which give falsely positive identification with ninhydrin detection). The stereospecific nature of the L-α-amino acid oxidase enables the investigator to quantitate the amount of L-α-amino acid in the presence of the D-α form. From an academic viewpoint, the extreme sensitivity and wide range of the detection system make it advantageous for the study of the enzyme itself. This automated method also may be employed to follow enzymatic reactions—e.g., those catalyzed by peptidases or racemases. The methodology is extremely convenient with good reagent stability and is much more sensitive than manometric technics.

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.

Determination of Free -Proline and -Leucine in the Brains of Mutant Mice Lacking -Amino Acid Oxidase Activity

2001 ◽  
Vol 298 (2) ◽  
pp. 253-258 ◽  
Author(s):  
Kenji Hamase ◽  
Tomomi Inoue ◽  
Akiko Morikawa ◽  
Ryuichi Konno ◽  
Kiyoshi Zaitsu
Keyword(s):  
Amino Acid ◽  
Oxidase Activity ◽  
Mutant Mice ◽  
Acid Oxidase ◽  
Free Proline ◽  
Amino Acid Oxidase

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 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.

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