scholarly journals Mechanistic studies of the agmatine deiminase from Listeria monocytogenes

2016 ◽  
Vol 473 (11) ◽  
pp. 1553-1561 ◽  
Author(s):  
Charles A. Soares ◽  
Bryan Knuckley
Keyword(s):  
Listeria Monocytogenes ◽  
Catalytic Mechanism ◽  
Mechanistic Studies ◽  
New Class ◽  
Enzyme Superfamily ◽  
Agmatine Deiminase ◽  
Inhibition Studies

Mechanistic and inhibition studies of the agmatine deiminase found in Listeria monocytogenes reveal a novel catalytic mechanism for the guanidinium-modifying enzyme superfamily. The results of the present study suggest that a new class of mechanism-based inactivators is needed.

scholarly journals Cu/Pd-catalyzed borocarbonylative trifunctionalization of alkynes and allenes: synthesis of β-geminal-diboryl ketones

2021 ◽  
Author(s):  
Yang Yuan ◽  
Fu-Peng Wu ◽  
Anke Spannenberg ◽  
Xiao-Feng Wu
Keyword(s):  
Organic Synthesis ◽  
Functional Group ◽  
Building Blocks ◽  
Mechanistic Studies ◽  
Efficient Strategy ◽  
New Class ◽  
Reaction Proceeds

AbstractFunctionalized bisboryl compounds have recently emerged as a new class of synthetically useful building blocks in organic synthesis. Herein, we report an efficient strategy to synthesize β-geminal-diboryl ketones enabled by a Cu/Pd-catalyzed borocarbonylative trifunctionalization of readily available alkynes and allenes. This reaction promises to be a useful method for the synthesis of functionalized β-geminal-diboryl ketones with broad functional group tolerance. Mechanistic studies suggest that the reaction proceeds through borocarbonylation/hydroboration cascade of both alkynes and allenes.

scholarly journals Lmo0036, an ornithine and putrescine carbamoyltransferase in Listeria monocytogenes, participates in arginine deiminase and agmatine deiminase pathways and mediates acid tolerance

Microbiology ◽  
2011 ◽  
Vol 157 (11) ◽  
pp. 3150-3161 ◽  
Author(s):  
Jianshun Chen ◽  
Changyong Cheng ◽  
Ye Xia ◽  
Hanxin Zhao ◽  
Chun Fang ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Foodborne Pathogen ◽  
Acid Tolerance ◽  
Arginine Deiminase ◽  
Transcriptional Level ◽  
Acidic Conditions ◽  
Acidic Environments ◽  
Agmatine Deiminase

Listeria monocytogenes is a foodborne pathogen causing listeriosis. Acid is one of the stresses that foodborne pathogens encounter most frequently. The ability to survive and proliferate in acidic environments is a prerequisite for infection. However, there is limited knowledge about the molecular basis of adaptation of L. monocytogenes to acid. Arginine deiminase (ADI) and agmatine deiminase (AgDI) systems are implicated in bacterial tolerance to acidic environments. Homologues of ADI and AgDI systems have been found in L. monocytogenes lineages I and II strains. Sequence analysis indicated that lmo0036 encodes a putative carbamoyltransferase containing conserved motifs and residues important for substrate binding. Lmo0036 acted as an ornithine carbamoyltransferase and putrescine carbamoyltransferase, representing the first example, to our knowledge, that catalyses reversible ornithine and putrescine carbamoyltransfer reactions. Catabolic ornithine and putrescine carbamoyltransfer reactions constitute the second step of ADI and AgDI pathways. However, the equilibrium of in vitro carbamoyltransfer reactions was overwhelmingly towards the anabolic direction, suggesting that catabolic carbamoyltransferase was probably the limiting step of the pathways. lmo0036 was induced at the transcriptional level when L. monocytogenes was subjected to low-pH stress. Its expression product in Escherichia coli exhibited higher catabolic carbamoyltransfer activities under acidic conditions. Consistently, absence of this enzyme impaired the growth of Listeria under mild acidic conditions (pH 4.8) and reduced its survival in synthetic human gastric fluid (pH 2.5), and corresponded to a loss in ammonia production, indicating that Lmo0036 was responsible for acid tolerance at both sublethal and lethal pH levels. Furthermore, Lmo0036 played a possible role in Listeria virulence.

ChemInform Abstract: Quinone-Annonaceous Acetogenins: Synthesis and Complex I Inhibition Studies of a New Class of Natural Product Hybrids.

ChemInform ◽  
2010 ◽  
Vol 33 (5) ◽  
pp. no-no
Author(s):  
Sabine Arndt ◽  
Ulrich Emde ◽  
Stefan Baeurle ◽  
Thorsten Friedrich ◽  
Lutz Grubert ◽  
...  
Keyword(s):  
Natural Product ◽  
Complex I ◽  
Annonaceous Acetogenins ◽  
New Class ◽  
Inhibition Studies

scholarly journals Steady-state kinetics of malonyl-CoA synthetase from Bradyrhizobium japonicum and evidence for malonyl-AMP formation in the reaction

1994 ◽  
Vol 297 (2) ◽  
pp. 327-333 ◽  
Author(s):  
Y S Kim ◽  
S W Kang
Keyword(s):  
Steady State ◽  
Bradyrhizobium Japonicum ◽  
Initial Velocity ◽  
Catalytic Mechanism ◽  
Kinetic Mechanism ◽  
Product Inhibition ◽  
Steady State Kinetics ◽  
Malonyl Coa ◽  
Michaelis Constants ◽  
Inhibition Studies

Malonyl-CoA synthetase catalyses the formation of malonyl-CoA directly from malonate and CoA with hydrolysis of ATP into AMP and PP1. The catalytic mechanism of malonyl-CoA synthetase from Bradyrhizobium japonicum was investigated by steady-state kinetics. Initial-velocity studies and the product-inhibition studies with AMP and PPi strongly suggested ordered Bi Uni Uni Bi Ping Pong Ter Ter system as the most probable steady-state kinetic mechanism of malonyl-CoA synthetase. Michaelis constants were 61 microM, 260 microM and 42 microM for ATP, malonate and CoA respectively, and the value for Vmax, was 11.2 microM/min. The t.l.c. analysis of the 32P-labelled products in a reaction mixture containing [gamma-32P]ATP in the absence of CoA showed that PPi was produced after the sequential addition of ATP and malonate. Formation of malonyl-AMP, suggested as an intermediate in the kinetically deduced mechanism, was confirmed by the analysis of 31P-n.m.r. spectra of an AMP product isolated from the 18O-transfer experiment using [18O]malonate. The 31P-n.m.r. signal of the AMP product appeared at 0.024 p.p.m. apart from that of [16O4]AMP, indicating that one atom of 18O transferred from [18O]malonate to AMP through the formation of malonyl-AMP. Formation of malonyl-AMP was also confirmed through the t.l.c. analysis of reaction mixture containing [alpha-32P]ATP. These results strongly support the ordered Bi Uni Uni Bi Pin Pong Ter Ter mechanism deduced from initial-velocity and product-inhibition studies.

scholarly journals Investigation of the Catalytic Mechanism of the Hotdog-Fold Enzyme Superfamily Pseudomonas sp. Strain CBS3 4-Hydroxybenzoyl-CoA Thioesterase

Biochemistry ◽  
2012 ◽  
Vol 51 (3) ◽  
pp. 786-794 ◽  
Author(s):  
Zhihao Zhuang ◽  
John Latham ◽  
Feng Song ◽  
Wenhai Zhang ◽  
Michael Trujillo ◽  
...  
Keyword(s):  
Catalytic Mechanism ◽  
Pseudomonas Sp ◽  
Enzyme Superfamily ◽  
Hotdog Fold

scholarly journals A catalytic mechanism for the enzyme benzylamine oxidase from pig plasma

1972 ◽  
Vol 130 (3) ◽  
pp. 713-728 ◽  
Author(s):  
C. E. Taylor ◽  
R. S. Taylor ◽  
C. Rasmussen ◽  
P. F. Knowles
Keyword(s):  
Catalytic Mechanism ◽  
Product Inhibition ◽  
Chemical Mechanism ◽  
Strictly Anaerobic ◽  
Anaerobic Conditions ◽  
Independent Evidence ◽  
Product Release ◽  
Benzylamine Oxidase ◽  
Inhibition Studies ◽  
Substrate Addition

Initial-velocity and product-inhibition studies on the enzyme benzylamine oxidase from pig plasma indicate that the order of substrate addition and product release is benzylamine on, ammonia off, oxygen on, hydrogen peroxide off, benzaldehyde off. Ammonia, but not benzaldehyde, is released under strictly anaerobic conditions which provides independent evidence for this order. Benzyl alcohol is a substrate for the enzyme. A chemical mechanism consistent with all the data is proposed.

Mechanistic and inhibition studies of chorismate-utilizing enzymes

2005 ◽  
Vol 33 (4) ◽  
pp. 763-766 ◽  
Author(s):  
O. Kerbarh ◽  
E.M.M. Bulloch ◽  
R.J. Payne ◽  
T. Sahr ◽  
F. Rébeillé ◽  
...  
Keyword(s):  
Catalytic Mechanism ◽  
Higher Plants ◽  
Three Dimensional ◽  
Antimicrobial Effect ◽  
Three Dimensional Model ◽  
Antimicrobial Drugs ◽  
Apicomplexan Parasites ◽  
Covalent Intermediate ◽  
Inhibition Studies ◽  
First Time

The shikimate biosynthetic pathway is utilized in algae, higher plants, bacteria, fungi and apicomplexan parasites; it involves seven enzymatic steps in which phosphoenolpyruvate and erythrose 4-phosphate are converted into chorismate. In Escherichia coli, five chorismate-utilizing enzymes catalyse the synthesis of aromatic compounds such as L-phenylalanine, L-tyrosine, L-tryptophan, folate, ubiquinone and siderophores such as yersiniabactin and enterobactin. As mammals do not possess such a biosynthetic system, the enzymes involved in the pathway have aroused considerable interest as potential targets for the development of antimicrobial drugs and herbicides. As an initiative to investigate the mechanism of some of these enzymes, we showed that the antimicrobial effect of (6S)-6-fluoroshikimate is the result of irreversible inhibition of 4-amino-4-deoxychorismate synthase by 2-fluorochorismate. Based on this study, a catalytic mechanism for this enzyme was proposed, in which the residue Lys-274 is involved in the formation of a covalent intermediate. In another study, Yersinia enterocolitica Irp9, which is involved in the biosynthesis of the siderophore yersiniabactin, was for the first time biochemically characterized and shown to catalyse the formation of salicylate from chorismate via isochorismate as a reaction intermediate. A three-dimensional model for this enzyme was constructed that will guide the search for potent inhibitors of salicylate formation, and hence of bacterial iron uptake.

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