1202-66-0Relevant articles and documents
Evidence of a coupled mechanism between monoamine oxidase and peroxidase in the metabolism of tyramine by rat intestinal mitochondria
Valoti, Massimo,Moron, Jose A.,Benocci, Alberto,Sgaragli, Giampietro,Unzeta, Mercedes
, p. 37 - 43 (1998)
The relationship between monoamine oxidase (EC 1.4.3.4; MAO) and peroxidase (EC 1.11.1.7; POD) in the metabolism of tyramine was investigated using the crude mitochondrial fraction of rat intestine. When tyramine was incubated with mitochondria, the formation of the peroxidase-catalysed oxidation product, 2,2'-dihydroxy-5,5'-bis(ethylamino)diphenyl (dityramine), identified by mass spectrometric analysis, was monitored spectrophotometrically. After an initial lag time, the formation rate of dityramine was linear up to 2 hr, amounting to 17 nmol x hr-1 x mg protein-1. A similar value was found for the oxidative deamination of tyramine catalysed by intestinal MAO. Either 10-3 M clorgyline or 10-3 M NaCN suppressed this reaction by completely inhibiting MAO or POD, respectively. In the former case, however, addition of H2O2 to the incubation mixture promptly started the reaction. Selective inhibition of MAO-A and MAO-B was achieved with 3 x 10-7 M clorgyline and 3 x 10-7 M deprenyl, respectively, and the formation rate of dityramine decreased in a corresponding manner. Preincubation with histamine or spermidine reduced the lag time without affecting the steady-state reaction rate. Higher levels of dityramine were also detected in vivo in rat intestine after oral administration of tyramine. These results indicate that the peroxidase-dependent metabolism of tyramine in the gut may be driven by H2O2 produced by MAO activities and that MAO-A is mainly responsible for this process, as well as for the oxidative deamination of tyramine.
SN2 substitution on sp2 nitrogen of protonated oxime
Mori, Seiji,Uchiyama, Katsuya,Hayashi, Yujiro,Narasaka, Koichi,Nakamura, Eiichi
, p. 111 - 112 (1998)
Theoretical studies on intramolecular nucleophilic displacement of the prolonated oxime oxygen willi an aryl ring revealed that the substitution reaction on the sp2 nitrogen atom is a low energy process. This seemingly anomalous substitution is due to the low-lying σ*-orbital of the O-protonated oxime. The theoretical conclusion received experimental support.
Characterization of arylalkylamine n-acyltransferase from tribolium castaneum: an investigation into a potential next-generation insecticide target
Anderson, Ryan L.,Chen, Yu,Gelis, Ioannis,Leahy, James W.,Lewandowski, Eric M.,Mccaskey, Angelica N.,Merkler, David J.,O'flynn, Brian G.,Prins, Karin Claire,Rios-Guzman, Nasha M.,Shepherd, Britney A.,Suarez, Gabriela
, p. 513 - 523 (2020/03/11)
The growing issue of insecticide resistance has meant the identification of novel insecticide targets has never been more important. Arylalkylamine N-acyltransferases (AANATs) have been suggested as a potential new target. These promiscuous enzymes are involved in the N-acylation of biogenic amines to form N-acylamides. In insects, this process is a key step in melanism, hardening of the cuticle, removal of biogenic amines, and in the biosynthesis of fatty acid amides. The unique nature of each AANAT isoform characterized indicates each organism accommodates an assembly of discrete AANATs relatively exclusive to that organism. This implies a high potential for selectivity in insecticide design, while also maintaining polypharmacology. Presented here is a thorough kinetic and structural analysis of AANAT found in one of the most common secondary pests of all plant commodities in the world, Tribolium castaneum. The enzyme, named TcAANAT0, catalyzes the formation of short-chain N-acylarylalkylamines, with short-chain acyl-CoAs (C2-C10), benzoyl-CoA, and succinyl-CoA functioning in the role of acyl donor. Recombinant TcAANAT0 was expressed and purified from E. coli and was used to investigate the kinetic and chemical mechanism of catalysis. The kinetic mechanism is an ordered sequential mechanism with the acyl-CoA binding first. pH-rate profiles and site-directed mutagenesis studies identified amino acids critical to catalysis, providing insights about the chemical mechanism of TcAANAT0. A crystal structure was obtained for TcAANAT0 bound to acetyl-CoA, revealing valuable information about its active site. This combination of kinetic analysis and crystallography alongside mutagenesis and sequence analysis shines light on some approaches possible for targeting TcAANAT0 and other AANATs for novel insecticide design.
Comprehensive kinetic and substrate specificity analysis of an arylsulfatase from Helix pomatia using mass spectrometry
Correia, Mário S.P.,Ballet, Caroline,Meistermann, Hannes,Conway, Louis P.,Globisch, Daniel
, p. 955 - 962 (2019/02/09)
Sulfatases hydrolyze sulfated metabolites to their corresponding alcohols and are present in all domains of life. These enzymes have found major application in metabolic investigation of drugs, doping control analysis and recently in metabolomics. Interest in sulfatases has increased due to a link between metabolic processes involving sulfated metabolites and pathophysiological conditions in humans. Herein, we present the first comprehensive substrate specificity and kinetic analysis of the most commonly used arylsulfatase extracted from the snail Helix pomatia. In the past, this enzyme has been used in the form of a crude mixture of enzymes, however, recently we have purified this sulfatase for a new application in metabolomics-driven discovery of sulfated metabolites. To evaluate the substrate specificity of this promiscuous sulfatase, we have synthesized a series of new sulfated metabolites of diverse structure and employed a mass spectrometric assay for kinetic substrate hydrolysis evaluation. Our analysis of the purified enzyme revealed that the sulfatase has a strong preference for metabolites with a bi- or tricyclic aromatic scaffold and to a lesser extent for monocyclic aromatic phenols. This metabolite library and mass spectrometric method can be applied for the characterization of other sulfatases from humans and gut microbiota to investigate their involvement in disease development.
New enzymatic and mass spectrometric methodology for the selective investigation of gut microbiota-derived metabolites
Ballet, Caroline,Correia, Mário S. P.,Conway, Louis P.,Locher, Theresa L.,Lehmann, Laura C.,Garg, Neeraj,Vujasinovic, Miroslav,Deindl, Sebastian,L?hr, J.-Matthias,Globisch, Daniel
, p. 6233 - 6239 (2018/08/07)
Gut microbiota significantly impact human physiology through metabolic interaction. Selective investigation of the co-metabolism of bacteria and their human host is a challenging task and methods for their analysis are limited. One class of metabolites associated with this co-metabolism are O-sulfated compounds. Herein, we describe the development of a new enzymatic assay for the selective mass spectrometric investigation of this phase II modification class. Analysis of human urine and fecal samples resulted in the detection of 206 sulfated metabolites, which is three times more than reported in the Human Metabolome Database. We confirmed the chemical structure of 36 sulfated metabolites including unknown and commonly reported microbiota-derived sulfated metabolites using synthesized internal standards and mass spectrometric fragmentation experiments. Our findings demonstrate that enzymatic sample pre-treatment combined with state-of-the-art metabolomics analysis represents a new and efficient strategy for the discovery of unknown microbiota-derived metabolites in human samples. Our described approach can be adapted for the targeted investigation of other metabolite classes as well as the discovery of biomarkers for diseases affected by microbiota.
An Unconventional Reaction of 2,2-Diazido Acylacetates with Amines
H?ring, Andreas P.,Biallas, Phillip,Kirsch, Stefan F.
supporting information, p. 1526 - 1539 (2017/04/01)
We have discovered that 2,2-diazido acylacetates, a class of compounds with essentially unknown reactivity, can be coupled to amines through a new strategy that does not involve any reagents. 2,2-Diazido acetate is the unconventional leaving group under carbon–carbon bond cleavage. This reaction leads to the construction of amide bonds, tolerates various functionalities and is performed equally well in numerous solvents under experimentally simple conditions. We also demonstrate that the isolation of the 2,2-diazido acylacetate compounds can be circumvented: Acylacetates were easily fragmented when treated with (Bu4N)N3 and iodine in the presence of an amine at room temperature. By using this method, a broad range of acylacetates with various structural motifs were directly transformed into amides.
Photoinduced Vitamin B12-Catalysis for Deprotection of (Allyloxy)arenes
Giedyk, Maciej,Turkowska, Joanna,Lepak, Sandra,Marculewicz, Marcin,ó Proinsias, Keith,Gryko, Dorota
supporting information, p. 2670 - 2673 (2017/05/24)
Vitamin B12 is a natural cobalt complex that, while reduced to the "supernucleophilic" Co(I) form, can easily react with electrophiles via an SN2 mechanism. It is also shown to react via an SN2′ mechanism with allylic compounds allowing for photochemical deprotection of (allyloxy)arenes. A sustainable alternative to commonly used noble metal-catalyzed deprotection reactions is presented.
Chemoselective N-acetylation of primary aliphatic amines promoted by pivalic or acetic acid using ethyl acetate as an acetyl donor
Yoshida, Tomoki,Kawamura, Shimpei,Nakata, Kenya
supporting information, p. 1181 - 1184 (2017/03/02)
The combination of pivalic or acetic acid as a promoter and EtOAc as a solvent and acetyl donor proved to be efficient for the chemoselective N-acetylation of primary aliphatic amines to afford the corresponding acetamides. We developed a simple and convenient approach, which requires mild reaction conditions. Competitive inter- and intramolecular reactions between aliphatic amines, alcohols, and aromatic amines were examined, and chemoselectivity was achieved by adjusting the conditions of the reaction.
Ezrin inhibitors and methods of making and using
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Page/Page column 57, (2017/01/05)
The invention encompasses compound and pharmaceutical composition comprising the compound of the following Formula (I): or pharmaceutically acceptable salts or prodrugs thereof, that are useful for inhibiting ezrin protein in a cell or for inhibiting the growth of a cancer cell.
Design, synthesis and biological evaluation of ezrin inhibitors targeting metastatic osteosarcoma
Paige, Mikell,Kosturko, George,Bulut, Güllay,Miessau, Matthew,Rahim, Said,Toretsky, Jeffrey A.,Brown, Milton L.,üren, Aykut
, p. 478 - 487 (2014/01/17)
Respiratory failure due to pulmonary metastasis is the major cause of death for patients with osteosarcoma. However, the molecular basis for metastasis of osteosarcoma is poorly understood. Recently, ezrin, a member of the ERM family of proteins, has been associated with osteosarcoma metastasis to the lungs. The small molecule NSC 668394 was identified to bind to ezrin, inhibit in vitro and in vivo cell migration, invasion, and metastatic colony survival. Reported herein are the design and synthesis of analogues of NSC 668394, and subsequent functional ezrin inhibition studies. The binding affinity was characterized by surface plasmon resonance technique. Cell migration and invasion activity was determined by electrical cell impedance methodology. Optimization of a series of heterocyclic-dione analogues led to the discovery of compounds 21k and 21m as potential novel antimetastatic agents.
