Construction of a d-Amino Acid Oxidase Reactor Based on Magnetic Nanoparticles Modified by a Reactive Polymer and Its Application in Screening Enzyme Inhibitors

2014 ◽  
Vol 6 (15) ◽  
pp. 12979-12987 ◽  
Author(s):  
Xiaoyu Mu ◽  
Juan Qiao ◽  
Li Qi ◽  
Ying Liu ◽  
Huimin Ma
2000 ◽  
Vol 72 (3) ◽  
pp. 373-384 ◽  
Author(s):  
Benjamin Adams ◽  
B. Svante Axelsson ◽  
Kenneth J. M. Beresford ◽  
Nicola J. Church ◽  
Philip A. Spencer ◽  
...  

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.


2008 ◽  
Vol 31 (4) ◽  
pp. 557-563 ◽  
Author(s):  
Hao-Chieh Hsieh ◽  
I-Ching Kuan ◽  
Shiow-Ling Lee ◽  
Gee-Yeng Tien ◽  
Yi-Jen Wang ◽  
...  

1996 ◽  
Vol 76 (06) ◽  
pp. 0993-0997
Author(s):  
Zhao-Yan Li ◽  
Xiao-Wei Wu ◽  
Tie-Fu Yu ◽  
Eric C-Y Lian

SummaryBy means of CM-Sephadex C-25, DEAE-Sephadex A-50, Sephadex G-200, and Sephadex G-75 chromatographies, a lupus anticoagulant like protein (LALP) from Agkistrodon halys brevicaudus was purified. On SDS-PAGE, the purified LALP had a molecular weight of 25,500 daltons under non-reducing condition and 15,000 daltons under reducing condition. The isoelectric point was pH 5.6. Its N terminal amino acid sequencing revealed a mixture of 2 sequences: DCP(P/S)(D/G)WSSYEGH(C/R)Q(Q/K). It was devoid of phospho-lipaseA, fibrino(geno)lytic, 5′-nucleotidase, L-amino acid oxidase, phosphomonoesterase, phosphodiesterase and thrombin-like activities, which were found in crude venom. In the presence of LALP, PT, aPTT, and dRVVT of human plasma were markedly prolonged and its effects were concentration-dependent but time-independent. The inhibitory effect of LALP on the plasma clotting time was enhanced by decreasing phospholipid concentration in TTI test. The individual clotting factor activity was not affected by LALP when higher dilutions of LALP-plasma mixture were used for assay. Russell’s viper venom time was shortened when high phospholipid confirmatory reagent was used. Therefore, the protein has lupus anticoagulant property.


1982 ◽  
Vol 48 (03) ◽  
pp. 277-282 ◽  
Author(s):  
I Nathan ◽  
A Dvilansky ◽  
T Yirmiyahu ◽  
M Aharon ◽  
A Livne

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.


Author(s):  
Hong Wei ◽  
Zuyue Chen ◽  
Ari Koivisto ◽  
Antti Pertovaara

Abstract Background Earlier studies show that endogenous sphingolipids can induce pain hypersensitivity, activation of spinal astrocytes, release of proinflammatory cytokines and activation of TRPM3 channel. Here we studied whether the development of pain hypersensitivity induced by sphingolipids in the spinal cord can be prevented by pharmacological inhibition of potential downstream mechanisms that we hypothesized to include TRPM3, σ1 and NMDA receptors, gap junctions and D-amino acid oxidase. Methods Experiments were performed in adult male rats with a chronic intrathecal catheter for spinal drug administrations. Mechanical nociception was assessed with monofilaments and heat nociception with radiant heat. N,N-dimethylsphingosine (DMS) was administered to induce pain hypersensitivity. Ononetin, isosakuranetin, naringenin (TRPM3 antagonists), BD-1047 (σ1 receptor antagonist), carbenoxolone (a gap junction decoupler), MK-801 (NMDA receptor antagonist) and AS-057278 (inhibitor of D-amino acid oxidase, DAAO) were used to prevent the DMS-induced hypersensitivity, and pregnenolone sulphate (TRPM3 agonist) to recapitulate hypersensitivity. Results DMS alone produced within 15 min a dose-related mechanical hypersensitivity that lasted at least 24 h, without effect on heat nociception. Preemptive treatments with ononetin, isosakuranetin, naringenin, BD-1047, carbenoxolone, MK-801 or AS-057278 attenuated the development of the DMS-induced hypersensitivity, but had no effects when administered alone. Pregnenolone sulphate (TRPM3 agonist) alone induced a dose-related mechanical hypersensitivity that was prevented by ononetin, isosakuranetin and naringenin. Conclusions Among spinal pronociceptive mechanisms activated by DMS are TRPM3, gap junction coupling, the σ1 and NMDA receptors, and DAAO.


1983 ◽  
Vol 258 (6) ◽  
pp. 3799-3802
Author(s):  
K Yagi ◽  
F Tanaka ◽  
N Nakashima ◽  
K Yoshihara

1973 ◽  
Vol 248 (6) ◽  
pp. 1946-1955 ◽  
Author(s):  
Christopher T. Walsh ◽  
Elizabeth Krodel ◽  
Vincent Massey ◽  
Robert H. Abeles

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