Reaction of glycine with glyoxylate: Competing transaminations, aldol reactions, and decarboxylations

Conley, Mark; Mojica, Mike; Mohammed, F.; Chen, Ke; Napoline, J. Wesley; Pollet, Paméla; Wang, Jing; Krishnamurthy, Ramanarayanan; Liotta, Charles L.

doi:10.1002/poc.3709

Cited by 6 publications

(4 citation statements)

References 16 publications

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“…We therefore attribute the observed unavailability of glyoxylate during the reaction to the competing formation of vanadate-glyoxylate complexes as well as incorrect integration due to signal broadening. In contrast to previous studies at higher temperatures without metal catalysts, no direct decomposition products of glyoxylate (e.g., to HCO 3 – , oxalic acid, glycolic acid) were observed …”

Section: Results and Discussioncontrasting

confidence: 99%

“…In the context of transamination between biochemical substrates, mechanistic studies have been carried out on the slow catalyst-free reaction, which is limited to glyoxylate, and much is known about the stoichiometric formation of metal-imine complexes . However, following the original exploratory studies carried out in the 1950s mostly under high temperatures (70–100 °C), , little work has been done on the overall mechanism of transamination solely under catalysis by metal ions.…”

Section: Introductionmentioning

confidence: 99%

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Mechanistic Insight into Metal Ion-Catalyzed Transamination

et al. 2021

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Several classes of biological reactions that are mediated by an enzyme and a co-factor can occur, to a slower extent, not only without the enzyme but even without the co-factor, under catalysis by metal ions. This observation has led to the proposal that metabolic pathways progressively evolved from using inorganic catalysts to using organocatalysts of increasing complexity. Transamination, the biological process by which ammonia is transferred between amino acids and keto acids, has a mechanism that has been well studied under enzyme/co-factor catalysis and under co-factor catalysis, but the metal ion-catalyzed variant was generally studied mostly at high temperatures (70-100 ºC), and the details of its mechanism remain unclear. Here, we investigate which metal ions catalyze transamination under conditions relevant to biology (pH 7, 20-50 ºC) and study the mechanism in detail. Cu 2+ , Ni 2+ , Co 2+ and V 5+ were identified as the most active metal ions under these constraints. Kinetic, stereochemical and computational studies illuminate the mechanism of the reaction. Cu 2+ and Co 2+ are found to predominantly speed up the reaction by stabilizing a key imine intermediate. V 5+ is found to accelerate the reaction by increasing the acidity of the bound imine. Ni 2+ is found to do both to a limited extent. These results show that direct metal ion-catalyzed amino group transfer is highly favored even in the absence of cofactors or protein catalysts under biologically compatible reaction conditions.

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Section: Results and Discussioncontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mechanistic Insight into Metal Ion-Catalyzed Transamination

et al. 2021

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“…A significantly fast transamination reaction followed by the conversion of Ser to Gly could explain the higher assimilation of 15 N over 13 C. However, transport rates of 15 N into Ser do not fully support this as they were lower compared to those of Gly. Gly can also be biosynthesised from glyoxylate (Conley et al 2017;Caspi et al 2019). In this case, the transamination is mediated by alanine.…”

Section: Thaas Concentrationmentioning

confidence: 99%

Tracing carbon and nitrogen microbial assimilation in suspended particles in freshwaters

et al. 2022

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The dynamic interactions between dissolved organic matter (DOM) and particulate organic matter (POM) are central in nutrient cycling in freshwater ecosystems. However, the molecular-level mechanisms of such interactions are still poorly defined. Here, we study spatial differences in the chemical (i.e., individual proteinaceous amino acids) and microbial (i.e., 16S rRNA) composition of suspended sediments in the River Chew, UK. We then applied a compound-specific stable isotope probing (SIP) approach to test the potential assimilation of 13C,15N-glutamate (Glu) and 15N-NO3− into proteinaceous biomass by particle-associated microbial communities over a 72-h period. Our results demonstrate that the composition of suspended particles is strongly influenced by the effluent of sewage treatment works. Fluxes and percentages of assimilation of both isotopically labelled substrates into individual proteinaceous amino acids showed contrasting dynamics in processing at each site linked to primary biosynthetic metabolic pathways. Preferential assimilation of the organic molecule glutamate and evidence of its direct assimilation into newly synthesised biomass was obtained. Our approach provides quantitative molecular information on the mechanisms by which low molecular weight DOM is mineralised in the water column compared to an inorganic substrate. This is paramount for better understanding the processing and fate of organic matter in aquatic ecosystems.

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“…However, transport rates of 15 N into Ser do not fully support this as they were lower compared to the ones of Gly. Gly can also be synthesised from glyoxylate (Conley et al 2017;Caspi et al 2019). In this case, the transamination is mediated by alanine.…”

Section: C 𝟏𝟓 N-glu Treatmentmentioning

confidence: 99%

Tracing Carbon and Nitrogen Microbial Assimilation in Suspended Particles in Freshwaters

Mena-Rivera

Lloyd

Reay

et al. 2021

Preprint

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The dynamic interactions between dissolved organic matter (DOM) and particulate organic matter (POM) are central in nutrient cycling in freshwater ecosystems. However, the molecular-level mechanisms of such interactions are still poorly defined. Here, we study spatial differences in the chemical and molecular composition of suspended sediments in the River Chew, UK. We then applied a compound-specific stable isotope probing (SIP) approach to test the potential assimilation of 13C,15N-glutamate (Glu) and 15N-nitrate into proteinaceous biomass by particle-associated microbial communities over a 72-h period. Our results demonstrate that the composition of suspended sediments is strongly influenced by the effluent of sewage treatment works (STW). Fluxes and percentages of assimilation of both isotopically labelled substrates into individual proteinaceous amino acids (AAs) showed contrasting dynamics in processing at each site linked to primary biosynthetic metabolic pathways. Preferential assimilation of the organic molecule glutamate and evidence of its direct assimilation into newly synthesised biomass was obtained. Our approach provides quantitative molecular information on the mechanisms by which low molecular weight DOM is mineralised in the water column compared to an inorganic substrate. This is paramount for better understanding the processing and fate of organic matter in aquatic ecosystems.

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Reaction of glycine with glyoxylate: Competing transaminations, aldol reactions, and decarboxylations

Cited by 6 publications

References 16 publications

Mechanistic Insight into Metal Ion-Catalyzed Transamination

Mechanistic Insight into Metal Ion-Catalyzed Transamination

Tracing carbon and nitrogen microbial assimilation in suspended particles in freshwaters

Tracing Carbon and Nitrogen Microbial Assimilation in Suspended Particles in Freshwaters

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