phenylalanine metabolism

Pyrus pyrifolia (Asian pear) cell cultures respond to yeast extract (YE) treatment by accumulating benzoate-derived biphenyl phytoalexins, namely, noraucuparin and aucuparin. Biphenyl phytoalexins are defense-marker metabolites of the sub-tribe Malinae of the family Rosaceae. The substrates for biphenyl biosynthesis are benzoyl-CoA and malonyl-CoA, which combine in the presence of biphenyl synthase (BIS) to produce 3,5-dihydroxybiphneyl. In the non-β-oxidative pathway, benzoyl-CoA is directly derived from benzoic acid in a reaction catalyzed by benzoate-CoA ligase (BZL)...

Phenylketonuria (PKU) and less severe hyperphenylalaninemia (HPA) constitute the most common inborn error of amino acid metabolism, and is most often caused by defects in phenylalanine hydroxylase (PAH) function resulting in accumulation of Phe to neurotoxic levels. Despite the success of dietary intervention in preventing permanent neurological damage, individuals living with PKU clamor for additional non-dietary therapies. The bulk of disease-associated mutations are PAH missense variants, which occur throughout the entire 452 amino acid human PAH protein...

BACKGROUND: Serum creatinine, urea, and cystatin-c are standardly used for the evaluation of renal function in the clinic. However, some patients have chronic kidney disease but still retain kidney function; a conventional serum index in these patients can be completely normal. Serum amino acid levels can reflect subtle changes in metabolism and are closely related to renal function. Here, we investigated how amino acids change as renal impairment increases. METHODS: Subjects were divided into three groups by renal function glomerular filtration rate: healthy controls, patients with chronic kidney disease with normal kidney function, and patients with chronic kidney disease with decreased kidney function group...

Biostimulants are substances able to improve water and nutrient use efficiency and counteract stress factors by enhancing primary and secondary metabolism. Premise of the work was to exploit raw extracts from leaves (LE) or flowers (FE) of Borago officinalis L., to enhance yield and quality of Lactuca sativa 'Longifolia,' and to set up a protocol to assess their effects. To this aim, an integrated study on agronomic, physiological and biochemical aspects, including also a phenomic approach, has been adopted...

OBJECTIVE: We used targeted metabolomics to determine associations of maternal BMI and glucose levels with cord blood metabolites and associations of cord blood metabolites with newborn birth weight and adiposity in mother-offspring dyads. RESEARCH DESIGN AND METHODS: Targeted metabolomic assays were performed on cord blood serum samples from European ancestry, Afro-Caribbean, Thai, and Mexican American newborns (400 from each ancestry group) whose mothers participated in the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study and who had anthropometric measurements at birth...

Our objective was to comparatively profile the metabolite composition of primary hepatocellular carcinoma (HCC) tumors from alcoholic liver disease (ALD), hepatitis B virus (HBV)-infected, and hepatitis C virus (HCV)-infected cirrhotic patients. Primary HCC tumors were collected from ALD, HBV-infected, and HCV-infected cirrhotic patients (n=20 each). High-resolution magic-angle spinning proton nuclear magnetic resonance spectroscopy and metabonomic data analysis were performed to compare HCC tumors from the three groups...

Exogenous phenylalanine stunted annual ryegrass but not switchgrass or winter grain rye, with deuterium incorporation up to 3% from phenyalanine-d 8 . Toxicity to duckweed varied with illumination intensity and glucose uptake. Isotopic labeling of biomolecules through biosynthesis from deuterated precursors has successfully been employed for both structural studies and metabolic analysis. Phenylalanine is the precursor of many products synthesized by plants, including the monolignols used for synthesis of lignin...

As a catadromous species, salinity is a key parameter that affects gonadal development of Chinese mitten crab Eriocheir sinensis during reproductive migration. It is however unclear the effects of salinity on the gonadal development of male E. sinensis as well as their physiological responses to salinity during reproductive migration. This study investigated the effects of four salinities (0 ‰, 6 ‰, 12 ‰ and 18 ‰) on gonadal development, osmoregulation and metabolism of adult male E. sinensis over a 40-day period...

BACKGROUND: Lettuce is a significant source of antioxidants and bioactive compounds. Nitrate is a cardinal fertilizer in horticulture and influences vegetable yield and quality; however, the negative effects of nitrate on the biosynthesis of flavonoids require further study. It is expected that using fertilizers containing organic N could promote the synthesis of health-promoting compounds. RESULTS: Lettuces were hydroponically cultured in media containing 9 mM nitrate or 9 mM glycine for 4 weeks...

Breast cancer (BC) is the most common diagnosed cancer and the leading cause of cancer death in women worldwide. There is an obvious need for a better understanding of BC biology. Alterations in the serum metabolome of BC patients have been identified but their clinical significance remains elusive. We evaluated by 1H-Nuclear Magnetic Resonance (1H-NMR) spectroscopy, filtered plasma metabolome of 50 early (EBC) and 15 metastatic BC (MBC) patients. Using Principal Component Analysis, Partial Least-Squares Discriminant Analysis and Hierarchical Clustering we show that plasma levels of glucose, lactate, pyruvate, alanine, leucine, isoleucine, glutamate, glutamine, valine, lysine, glycine, threonine, tyrosine, phenylalanine, acetate, acetoacetate, β-hydroxy-butyrate, urea, creatine and creatinine are modulated across patients clusters...

Lrp/AsnC family regulators have been found in many bacteria as crucial regulators controlling diverse cellular processes. By genomic alignment, we found that SCO3361, an Lrp/AsnC family protein from Streptomyces coelicolor, shared the highest similarity to the SACE_Lrp from Saccharopolyspora erythraea. Deletion of SCO3361 led to dramatic reduction in actinorhodin (Act) production and delay in aerial mycelium formation and sporulation on solid media. Dissection of the mechanism underlying the function of SCO3361 in Act production revealed that it altered the transcription of the cluster-situated regulator gene actII-ORF4 by directly binding to its promoter...

BACKGROUND: Phenylketonuria (PKU) often requires a lifelong phenylalanine (Phe)-restricted diet. Introduction of 6R-tetrahydrobiopterin (BH4) has made a huge difference in the diets of patients with PKU. BH4 is the co-factor of the enzyme phenylalanine hydroxylase (PAH) and improves PAH activity and, thus, Phe tolerance in the diet. A limited number of published studies suggest a pharmacodynamic profile of BH4 more suitable to be administered in divided daily doses. METHODS: After a 72-h BH4 loading test, sapropterin was initiated in 50 responsive patients...

High-performance liquid chromatography-mass spectrometry (LC-MS) was used for comprehensive metabolomic fingerprinting of vanilla fruits prepared from the curing process. In this study, the metabolic changes of vanilla pods and vanilla beans were characterized using MS-based metabolomics to elucidate the biosynthesis of vanillin. The vanilla pods were significantly different from vanilla beans. Seven pathways of vanillin biosynthesis were constructed, namely, glucovanillin, glucose, cresol, capsaicin, vanillyl alcohol, tyrosine, and phenylalanine pathways...

Saccharomyces cerevisiae has been extensively engineered for optimizing its performance as a microbial cell factory to produce valuable aromatic compounds and their derivatives as bulk and fine chemicals. The production of heterologous aromatic molecules in yeast is achieved via engineering of the aromatic amino acid biosynthetic pathway. This pathway is connected to two pathways of the central carbon metabolism, and is highly regulated at the gene and protein level. These characteristics impose several challenges for tailoring it, and various modifications need to be applied in order to redirect the carbon flux towards the production of the desired compounds...

OBJECTIVES: It has been suggested that some amino acids are involved in the pathogenesis of autistic disorders. The aim of the study was to evaluate the plasma amino acids profile in young males with autism. METHODS: Total of 27 autistic boys (aged 2-10 years, the study group) without any metabolic disorders and 13 healthy boys (aged 2-9 years, control group) were included in the study. In all subjects fasting blood plasma free amino acids (both exogenous and endogenous) were quantitatively measured by high performance liquid chromatography with UV-VIS detection...

About 20 years ago an American study suggested that daily subcutaneous injections of a metabolically inactive insulin analogue with a single amino acid substitution (aspartic acid instead of phenylalanine) at position 25 of the B chain was as effective as intact insulin in preventing autoimmune diabetes in NOD mice. In this issue of Diabetologia Grönholm et al (DOI: 10.1007/s00125-017-4276-5 ) report that parenteral administration of the same insulin analogue has no preventive effect whatsoever on the development of diabetes in NOD mice; in fact, high doses of the metabolically inactive insulin accelerated disease development...

In a previous study, it was demonstrated that the toxic impact of titanium dioxide nanoparticles on Escherichia coli starts at 10 ppm and is closely related to the presence of little aggregates. It was also assumed that only a part of the bacterial population is able to adapt to this stress and attempts to survive. Proteomic analyses, supported by results from metabolomics, reveal that exposure of E. coli to nano-TiO2 induces two main effects on bacterial metabolism: firstly, the up-regulation of proteins and the increase of metabolites related to energy and growth metabolism; secondly, the down-regulation of other proteins resulting in an increase of metabolites, particularly amino acids...

Point of care (POC) diagnostics represents one of the fastest growing health care technology segments. Developments in microfabrication have led to the development of highly-sensitive nanocalorimeters ideal for directly measuring heat generated in POC biosensors. Here we present a novel nano-calorimeter-based biosensor design with differential sensing to eliminate common mode noise and capillary microfluidic channels for sample delivery to the thermoelectric sensor. The calorimeter has a resolution of 1.4 ± 0...

BACKGROUND: Phenylketonuria (PKU), a genetic metabolic disorder that is characterized by the inability to convert phenylalanine to tyrosine, leads to severe intellectual disability and other cerebral complications if left untreated. Dietary treatment, initiated soon after birth, prevents most brain-related complications. A leading hypothesis postulates that a shortage of brain monoamines may be associated with neurocognitive deficits that are observable even in early-treated PKU. However, there is a paucity of evidence as yet for this hypothesis...

Phenylacetic acid (PAA) is a fine chemical with a high industrial demand for its widespread uses. Whereas, microorganic synthesis of PAA is impeded by the formation of by-product phenethyl alcohol due to quick, endogenous, and superfluous conversion of aldehydes to their corresponding alcohols, which resulted in less conversation of PAA from aldehydes. In this study, an Escherichia coli K-12 MG1655 strain with reduced aromatic aldehyde reduction (RARE) that does duty for a platform for aromatic aldehyde biosynthesis was used to prompt more PAA biosynthesis...