Phenyllactate Research Articles

Relationship between circulating metabolites and diabetic retinopathy: a two-sample Mendelian randomization analysis

Diabetic retinopathy (DR) is the most frequent microvascular complication of diabetes mellitus, however, its underlying biological mechanisms remain poorly understood. We examined single nucleotide polymorphisms linked to 486 blood metabolites through extensive genome-wide association studies conducted on individuals of European ancestry. The FinnGen Biobank database served as a reference to define DR. Two-sample MR analysis was conducted to reveal the association between the levels of genetically predicted circulating metabolites and the susceptibility to DR. To validate the robustness of the obtained findings, sensitivity analyses with weighted median, weighted mode, and MR-Egger were conducted. 1-oleoylglycerophosphoethanolamine (odds ratio [OR] (OR per one standard deviation [SD] increase) = 0.414; 95% confidence interval [CI] 0.292–0.587; P = 7.613E−07, PFDR = 6.849E−06), pyroglutamine (OR per one SD increase = 0.414; 95% confidence interval [CI] 0.292–0.587; P = 8.31E−04, PFDR = 0.007), phenyllactate (PLA) (OR per one SD increase = 0.591; 95% confidence interval [CI] 0.418–0.836; P = 0.003, PFDR = 0.026), metoprolol acid metabolite (OR per one SD increase = 0.978; 95% confidence interval [CI] 0.962–0.993; P = 0.005, PFDR = 0.042), 10-undecenoate (OR per one SD increase = 0.788; 95% confidence interval [CI] 0.667–0.932; P = 0.005, PFDR = 0.049), erythritol (OR per one SD increase = 0.691; 95% confidence interval [CI] 0.513–0.932; P = 0.015, PFDR = 0.034), 1-stearoylglycerophosphoethanolamine (OR per one SD increase = 0.636; 95% confidence interval [CI] 0.431–0.937; P = 0.022, PFDR = 0.099), 1-arachidonoylglycerophosphoethanolamine (OR per one SD increase = 0.636; 95% confidence interval [CI] 0.431–0.937; P = 0.030, PFDR = 0.099) showed a significant causal relationship with DR and could have protective effects. stachydrine (OR per one SD increase = 1.146; 95% confidence interval [CI] 1.066–1.233; P = 2.270E−04, PFDR = 0.002), butyrylcarnitine (OR per one SD increase = 1.117; 95% confidence interval [CI] 1.023–1.219; P = 0.014, PFDR = 0.062), 5-oxoproline (OR per one SD increase = 1.569; 95% confidence interval [CI] 1.056–2.335; P = 0.026, PFDR = 0.082), and kynurenine (OR = 1.623; 95% CI 1.042–2.526; P = 0.041, PFDR = 0.097) were significantly associated with an increased risk of DR. This study identified metabolites have the potential to be considered prospective compounds for investigating the underlying mechanisms of DR and for selecting appropriate drug targets.

Metabolome-wide association study on physical activity

The underlying mechanisms linking physical activity to better health are not fully understood. Here we examined the associations between physical activity and small circulatory molecules, the metabolome, to highlight relevant biological pathways. We examined plasma metabolites associated with self-reported physical activity among 2217 participants from the Airwave Health Monitoring Study. Metabolic profiling was conducted using the mass spectrometry-based Metabolon platform (LC/GC–MS), measuring 828 known metabolites. We replicated our findings in an independent subset of the study (n = 2971) using untargeted LC–MS. Mendelian randomisation was carried out to investigate potential causal associations between physical activity, body mass index, and metabolites. Higher vigorous physical activity was associated (P < 0.05/828 = 6.03 × 10–5) with circulatory levels of 28 metabolites adjusted for age, sex and body mass index. The association was inverse for glutamate and diacylglycerol lipids, and direct for 3–4-hydroxyphenyllactate, phenyl lactate (PLA), alpha-hydroxy isovalerate, tiglylcarnitine, alpha-hydroxyisocaproate, 2-hydroxy-3-methylvalerate, isobutyrylcarnitine, imidazole lactate, methionine sulfone, indole lactate, plasmalogen lipids, pristanate and fumarate. In the replication panel, we found 23 untargeted LC–MS features annotated to the identified metabolites, for which we found nominal associations with the same direction of effect for three features annotated to 1-(1-enyl-palmitoyl)-2-oleoyl-GPC (P-16:0/18:1), 1-(1-enyl-palmitoyl)-2-linoleoyl-GPC (P-16:0/18:2), 1-stearoyl-2-dihomo-linolenoyl-GPC (18:0/20:3n3 or 6). Using Mendelian randomisation, we showed a potential causal relationship between body mass index and three identified metabolites. Circulatory metabolites are associated with physical activity and may play a role in mediating its health effects.

Effect of traditional chinese medicine (TCM) and its fermentation using Lactobacillus plantarum on ceftriaxone sodium-induced dysbacteriotic diarrhea in mice

BackgroundBuzhongyiqi decoction (BD), Sijunzi decoction (SD), and Shenlingbaizhu decoction (SHD) have been extensively used clinically for the treatment of diseases caused by spleen-Qi deficiency and microbial fermentation has historically been utilized in traditional Chinese medicine (TCM). This study aimed to investigate the mitigative effect of TCM and fermented TCM (FTCM) with Lactobacillus plantarum (LP) on antibiotic-associated diarrhea, and to select an optimal formula and then identify its compounds.MethodsDysbacteriosis in mice was induced by ceftriaxone sodium (CS). The mice were then treated with LP, BD, SD, SHD, fermented BD, fermented SD (FSD), and fermented SHD. Diarrhea indexes, the abundances of gut bacteria, intestinal morphometrics, and mRNA expressions of genes related to intestinal barrier function were assessed. Then, ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) were employed to identify and relatively quantify the compounds in the selected decoctions.ResultsCS significantly increased the fecal output weight, the total number of fecal output, and fecal water content, indicating the occurrence of diarrhea. Bacterial culture tests showed that the above symptoms were accompanied by the disruption of specific intestinal flora. TCM, LP, and FTCM alleviated the diarrhea index and recovered the intestinal microbiota. FTCM showed more advantageous than TCM or LP alone. The mRNA expressions of aquaporins (AQPs) and tight junctions (TJs) decreased by CS were enhanced by TCM, LP, and FTCM. In addition, through UHPLC-Q-TOF/MS, (S)-(-)-2-hydroxyisocaproic acid, L-methionine, 4-guanidinobutyric acid (4GBA), and phenyllactate (PLA) in SD and FSD were identified and relatively quantified.ConclusionsTCM, LP, and TCM fermented with LP alleviated CS-induced diarrhea symptoms, and improved the intestinal flora and barrier function. Four compounds including (S)-(-)-2-hydroxyisocaproic acid, L-methionine, 4GBA, and PLA in FSD, which were identified by UHPLC-Q-TOF/MS, might function in modulating intestinal flora and improving villi structure.

Genome, transcriptome and fermentation analyses of Lactobacillus plantarum LY-78 provide new insights into the mechanism of phenyllactate biosynthesis in lactic acid bacteria

Phenyllactate (PLA) is found in a variety of fermented foods and is a promising antibacterial agent, drug and plastic synthetic precursor. Previous studies have shown that PLA is a product of Phe catabolism in lactic acid bacteria (LAB), and PLA biosynthesis is mainly related to lactate dehydrogenases (LDHs). Here, the genome, transcriptome and fermentation characteristics of PLA-producing Lactobacillus plantarum LY-78 were studied. The fermentation experiments demonstrated that L. plantarum LY-78 possesses the ability to synthesize PLA de novo. Secondly, the genome and transcriptome analyses revealed candidate pathways, operons and key genes for PLA biosynthesis in the strain. Finally, genome-wide transcriptome analysis revealed significant changes in the expression profile of strain LY-78 in the absence and presence of PPA. Overall, this work demonstrates for the first time that PLA can be a by-product of Phe anabolism in LAB, provides new insights and evidence for elucidating the mechanism of PLA biosynthesis in LAB, and may provide new candidate genes and research strategies for future PLA biosynthesis applications.

Mathematical Model for Small Size Time Series Data of Bacterial Secondary Metabolic Pathways

Measuring the concentrations of metabolites and estimating the reaction rates of each reaction step consisting of metabolic pathways are significant for an improvement in microorganisms used in maximizing the production of materials. Although the reaction pathway must be identified for such an improvement, doing so is not easy. Numerous reaction steps have been reported; however, the actual reaction steps activated vary or change according to the conditions. Furthermore, to build mathematical models for a dynamical analysis, the reaction mechanisms and parameter values must be known; however, to date, sufficient information has yet to be published for many cases. In addition, experimental observations are expensive. A new mathematical approach that is applicable to small sample data, and that requires no detailed reaction information, is strongly needed. S-system is one such model that can use smaller samples than other ordinary differential equation models. We propose a simplified S-system to apply minimal quantities of samples for a dynamic analysis of the metabolic pathways. We applied the model to the phenyl lactate production pathway of Escherichia coli. The model obtained suggests that actually activated reaction steps and feedback are inhibitions within the pathway.

Novel fungal phenylpyruvate reductase belongs to d-isomer-specific 2-hydroxyacid dehydrogenase family

We discovered the phenyllactate (PLA)-producing fungal strain Wickerhamia fluorescens TK1 and purified phenylpyruvate reductase (PPR) from fungal cell-free extracts. The PPR used both NADPH and NADH as cofactors with more preference for the former. The enzyme reaction as well as the fungal culture produced optically active d-PLA. The gene for the PPR (pprA) was cloned and expressed in Escherichia coli cells. Purified preparations of both native and recombinant PPR used hydroxyphenylpyruvate, glyoxylate and hydroxypyruvate as substrates but not pyruvate, oxaloacetate or benzoylformate. The predicted PPR protein had sequence similarity to proteins in the d-isomer-specific 2-hydroxyacid dehydrogenase family. Phylogenetic analyses indicated that the predicted PPR protein together with fungal predicted proteins constitutes a novel group of glyoxylate/hydroxypyruvate reductases. The fungus efficiently converted phenylalanine and phenylpyruvate to d-PLA. These compounds up-regulated the transcription of pprA, suggesting that it plays a role in fungal phenylalanine metabolism.

Abstract 3813: Metabolites as biomarkers for ovarian cancer diagnosis and treatment

Abstract Ovarian cancer is the most lethal malignancy of the female reproductive track, mainly due to a lack of a reliable detection method during the early stages of this disease when it is most treatable. Currently, most cases of ovarian cancer are detected at stage IV due to a lack of symptoms. As current detection methods identify 50-60% of early stage ovarian cancer, it is important to identify novel biomarkers that are both specific and sensitive. In this study, we compared the comprehensive metabolic profile in normal, primary epithelial ovarian cancer (EOC), and metastatic tumors resulting from primary ovarian cancer (MOC) using gas chromatograph mass spectroscopy (GC/MS) or liquid chromatograph mass spectroscopy (LC/MS). Despite a small sample size, we were able to detect significant changes in energy utilization, shifting from oxidative phosphorylation to fatty acid utilization marked by increases in several fatty acids and carnitine metabolism_such as carnitine, acetylcarnitine, and propionylcartine _and by increases in fatty acid metabolism. EOC and MOC also displayed an enhanced oxidative stress response as indicated by increases in 2-aminobutyrate, phenylpyruvate, phenyllactate (PLA), and several isoforms of tocopherols. By using this method, we have also identified novel metabolites in the ovary, specifically N-acetylasparate (NAA) and N-acetyl-aspartyl-glutamate (NAAG), for which a biological function has yet to be determined. Using these findings, potential biomarkers can be identified for both preliminary cancer diagnosis and metastatic disease progression. Supported by NCI CA 124630 (SSK). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3813. doi:10.1158/1538-7445.AM2011-3813

Bioconversion of Phenylpyruvate to Phenyllactate: Gene Cloning, Expression, and Enzymatic Characterization of d- and l1-Lactate Dehydrogenases from Lactobacillus plantarum SK002

Two DNA fragments containing the entire coding sequences of lactate dehydrogenase (LDH; ldhL1 and ldhD), whose enzymes have high activity for bioconversion of phenylpyruvate (PPA) to phenyllactate (PLA), were amplified from Lactobacillus plantarum SK002 using PCR. Sequencing showed open reading frames of 963 bp (ldhL1) and 999 bp (ldhD) encoding putative proteins of 320 and 332 amino acid residues, respectively. The LDH genes were cloned into an expression vector pET-22b(+) and expressed in Escherichia coli BL21(DE3). The purified recombinant L1-LDH and D-LDH had approximate (SDS-PAGE) molecular weights of 35 and 40 kDa, respectively. L1-LDH and D-LDH had PPA bioconversion specific activities of 71.06 and 215.84 U/mg with K (m) values of 3.96 and 5.4 mM, respectively. The rL1-LDH and rD-LDH showed maximum enzyme activity at 30 and 40 degrees C while both had optimum activity at pH 6.0. L1-LDH exhibited a higher pH and temperature stability than D-LDH. The results show that the his-tagged L. plantarum SK002 D- and L1-LDHs are efficient catalysts for bioconversion of PPA to PLA.

Measurement of Phenyllactate, Phenylacetate, and Phenylpyruvate by Negative Ion Chemical Ionization–Gas Chromatography/Mass Spectrometry in Brain of Mouse Genetic Models of Phenylketonuria and Non-Phenylketonuria Hyperphenylalaninemia

Phenylketonuria (PKU) (OMIM 261600) is the first Mendelian disease to have an identified chemical cause of impaired cognitive development. The disease is accompanied by hyperphenylalaninemia (HPA) and elevated levels of phenylalanine metabolites (phenylacetate (PAA), phenyllactate (PLA), and phenylpyruvate (PPA)) in body fluids. Here we describe a method to determine the concentrations of PAA, PPA, and PLA in the brain of normal and mutant orthologous mice, the latter being models of human PKU and non-PKU HPA. Stable isotope dilution techniques are employed with the use of [2H5]-phenylacetic acid and [2,3,3-2H3]-3-phenyllactic acid as internal standards. Negative ion chemical ionization (NICI)–GC/MS analyses are performed on the pentafluorobenzyl ester derivatives formed in situ in brain homogenates. Unstable PPA in the homogenate is reduced by NaB2H4 to stable PLA, which is labeled with a single deuterium and discriminated from endogenous PLA in the mass spectrometer on that basis. The method demonstrates that these metabolites are easily measured in normal mouse brain and are elevated moderately in HPA mice and greatly in PKU mice. However, their concentrations are not sufficient in PKU to be “toxic”; phenylalanine itself remains the chemical candidate causing impaired cognitive development.

X-ray structure of two complexes of the Y143F flavocytochrome b2 mutant crystallized in the Presence of lactate or phenyl lactate

X-ray structure of two complexes of the Y143F flavocytochrome b2 mutant crystallized in the Presence of lactate or phenyl lactate

High-resolution structure of the complex between carboxypeptidase A andL-phenyl lactate

The X-ray structures of native carboxypeptidase A and of the enzyme-inhibitor complex with L-phenyl lactate have been refined at 1.54 and 1.45 A resolution to R factors of 0.151 and 0.161, respectively. Crystals of the complex were isomorphous with the native crystals (space group P2(1), a = 51.60, b = 60.27, c = 47.25 A, beta = 97.27 degrees ). The high-resolution electron density allowed correction of many side-chain positions in the classical carboxypeptidase A model. This reflects the advantages of the high-quality complete synchrotron data collected with an imaging plate detector. The conformational changes in the active centre of the enzyme upon binding of the inhibitor are restricted to only two residues, Tyr248 and Arg145. L-Phenyl lactate is bound in the S1' pocket and forms hydrogen bonds to Arg145, Glu270 and to the zinc-bound water molecule. The present structure provides an explanation for the higher stability of the complexes with the products of esterolysis in comparison with those of amidolysis. This is consistent with the finding that product release is rate limiting for esters but not for peptides.

The Broad-specificity, Membrane-bound Lactate Dehydrogenase of Neisseria gonorrhoeae: Ties to Aromatic Metabolism

Neisseria gonorrhoeae can convert phenyllactate (PL) to phenylalanine and 4-hydroxyphenyllactate (HPL) to tyrosine. This was demonstrated by nutritional and physiological approaches. The enzymic basis for this unusual ability was shown to be the broad specificity of a particulate, unidirectional, pyridine-nucleotide-independent lactate dehydrogenase. This enzyme, denoted [iLDH], has been implicated in a pathogenic mechanism whereby host-derived lactate is linked to increased gonococcal oxygen consumption and electron transport. A similar role for HPL, a metabolite available in human host tissues, may provide a selective basis to explain evolution of broadened [iLDH] specificity in Neisseria. The interplay between aromatic metabolism and [iLDH] suggests new approaches for manipulating the host-pathogen relationship.

Effects of phenylalanine and its deaminated metabolites on Na+,K+-ATPase activity in synaptosomes from rat brain.

The effects of phenylalanine (PHE) and its deaminated metabolites phenylpyruvate (PHP), phenyllactate (PHL) and phenylacetate (PHA) on sodium and potassium activated adenosinetriphosphatase (Na+,K+-ATPase) in synaptosomes from rat brain were investigated. At very low concentrations (5-10 microM). PHE, PHL and PHA inhibited the activity, while PHP stimulated the activity. At intermediate concentrations (50-100 microM), all compounds had no effect, but at higher (0.5-1.0 mM) concentrations they inhibited the enzyme activity. Thus all the compounds tested showed a biphasic effect on the enzyme activity. Hydroxylamine inhibited the Na+,K+-ATPase activity when present alone; simultaneous addition of hydroxylamine and PHE, however, eliminated the inhibitory effects of each other. Reversal of mutual inhibition also occurred in the presence of hydroxylamine and very low (5-10 microM) concentrations of PHL or PHA. The inhibitory effects of PHE at aLl concentrations, and of PHL or PHA at low concentrations, were also eliminated in the presence of EGTA. The data indicate that inhibition of brain membrane Na+,K+-ATPase by PHE and by low concentrations of PHL and PHA may involve metal ions, but that the inhibition by high concentrations of these metabolites must occur by a different mechanism. Since Na+,K+-ATPase plays a central role in neuronal function, and the presence of excess PHE and its deaminated metabolites occurs in brain tissue under conditions of experimentally induced hyperphenylalaninemia and genetic phenylketonuria, the neurologic impairment in experimental and genetic PKU may in part be related to the deleterious effects of these compounds on brain ATPase.

Effect of succinimide and other drugs on oxalate excretion by rats.

Succinimide, phenyl lactate, n-heptanoate, oxamic hydrazide, 2-oxoglutarate and ethinyl oestradiol all failed to reduce the urinary excretion of oxalic acid in male Wistar and Sprague-Dawley rats. The

Selective Inhibition of Respiration of Pigmented S91 Mouse Melanomas by Phenyl Lactate, and the Possibly Related Effects on Growth&lt;xref ref-type="fn" rid="FN1"&gt;2&lt;/xref&gt;

Selective Inhibition of Respiration of Pigmented S91 Mouse Melanomas by Phenyl Lactate, and the Possibly Related Effects on Growth&lt;xref ref-type="fn" rid="FN1"&gt;2&lt;/xref&gt;

Phenylalanine metabolism: The production of phenylacetaldehyde by a Proteus species

In the Proteus suspension under study it was shown that phenylalanine, 2 2 Phenylalanine was oxidized with the production of phenyl pyruvate and free ammonia. Phenyl pyruvate was decarboxylated. The other substrates, however, did not produce or take up gas. No test was made for the metabolism of these compounds. phenyl pyruvate, phenyl acetate, mandelic acid, and phenyl lactate at a 12 μmoles/ml, level were noninhibitory to glucose oxidation if glucose was added at zero time. Benzoic acid and benzaldehyde at a level of 15 μmoles/ml, were somewhat inhibitory. Metabolism of phenylalanine and phenyl pyruvate by the Proteus suspension produced a volatile, sweet-smelling aromatic substance, the production of which was coincident with complete inhibition of glucose oxidation. This substance has been identified as phenylacetaldehyde. Added phenylacetaldehyde, 0.3 μmole/ml., completely prevented glucose oxidation. This compound completely prevented Proteus growth at a 4 μ-moles/ml. level. Although human metabolism and Proteus metabolism of phenylalanine are not necessarily alike, it is tempting to speculate that one of the toxic products of the Proteus suspension and of phenylketonurics is phenylacetaldehyde.