phenylalanine metabolism

A 9-month-old Turkish girl was admitted several times within 3 months to the hospital in reduced general condition and with extreme tachypnea. The patient had been diagnosed with phenylketonuria (PKU) in newborn screening and has been treated with a low phenylalanine diet and amino acid supplements. Each time an unexplained pronounced metabolic acidosis was noted, and the child was treated with sodium-bicarbonate and glucose-electrolyte infusions. The acidosis with only slightly abnormal glucose, normal lactate levels and pronounced ketonuria suggested a defect in ketone body utilization...

The diversity of phytophagous insects is largely attributable to speciation involving shifts between host plants. These shifts are mediated by the close interaction between insects and plant metabolites. However, there has been limited progress in understanding the chemical signatures that underlie host preferences. We use the pea aphid (Acyrthosiphon pisum) to address this problem. Host-associated races of pea aphid discriminate between plant species in race-specific ways. We combined metabolomic profiling of multiple plant species with behavioural tests on two A...

Colchicine was commonly used to artificially double chromosomes while the transcriptome changes in colchicine treated plants has rarely been characterized. To understand the molecular mechanism of colchicine on chromosome doubling, we characterized transcriptome data of diploid orchardgrass root after colchicine treatment. Our results showed that 3381 of differentially expressed genes (DEGs) were mainly affected by water stress, 1258 DEGs that were expressed significantly in sample DacR5tr but not in DacR5ck were considered to be mainly affected by colchicine and combination of water and colchicine...

To explore the effects of hot air (HA, 38 °C for 12 h) treatment on phenylpropanoid metabolism in cherry tomatoes, phenylpropanoid metabolite levels and the activities and expression of key enzymes were analyzed in HA-treated fruit. HA treatment enhanced phenylpropanoid metabolism, as evidenced by elevated levels of phenolics and flavonoids, higher activities of phenylalanine ammonia-lyase and cinnamate-4-hydroxylase, and up-regulated expression of LeCHS, LeCHI, LeF3H, and LeFLS. Levels of several phenylpropanoid metabolites were higher after HA treatment, including p-coumaric acid, caffeic acid, chlorogenic acid, isoquercitrin, quercetin, and rutin...

Drosophila melanogaster is increasingly used for study aging mechanism and evaluating anti-aging drugs, but the changes of metabolites and differences of metabolites change between male and female during the aging process are not well known. Metabolomics technology, a massive information provider, has promoted the understanding of metabolic profile and overall changes of metabolites in organism. In this study, (1)H NMR based metabonomics was employed to investigate the dynamic changes of metabolites in whole bodies of male and female Drosophila melanogaster at 3, 15, 30, 45days and to research the gender gap of metabolites changes in aging process...

Biomarker research in Parkinson's disease (PD) has long been dominated by measuring dopamine metabolites or alpha-synuclein in cerebrospinal fluid. However, these markers do not allow early detection, precise prognosis or monitoring of disease progression. Moreover, PD is now considered a multifactorial disease, which requires a more precise diagnosis and personalized medication to obtain optimal outcome. In recent years, advanced metabolite profiling of body fluids like serum/plasma, CSF or urine, known as "metabolomics", has become a powerful and promising tool to identify novel biomarkers or "metabolic fingerprints" characteristic for PD at various stages of disease...

We reassessed data from a previous study on the transcerebral net exchange of large neutral amino acids (LNAAs) using a novel mathematical model of blood-brain barrier (BBB) transport. The study included twelve healthy volunteers who received a 4-h intravenous lipopolysaccharide (LPS) infusion (total dose: 0·3 ng/kg), a human experimental model of the systemic inflammatory response during the early stages of sepsis. Cerebral blood flow and arterial-to-jugular venous LNAA concentrations were measured prior to and after LPS, and the BBB transport and brain extracellular concentrations of LNAAs were calculated...

Background: An elevated circulating cystathionine concentration, which arises in part from insufficiencies of vitamin B-6, B-12, or folate, has been shown to be associated with cardiovascular disease (CVD) risk. Hydrogen sulfide (H2S) is a gasotransmitter involved in vasodilation, neuromodulation, and inflammation. Most endogenously produced H2S is formed by pyridoxal phosphate (PLP)-dependent enzymes by noncanonical reactions of the transsulfuration pathway that yield H2S concurrently form lanthionine and homolanthionine...

BACKGROUND: Autosomal recessive mutations in DNAJC12, encoding a cochaperone of HSP70 with hitherto unknown function, were recently described to lead to hyperphenylalaninemia, central monoamine neurotransmitter (dopamine and serotonin) deficiency, dystonia and intellectual disability in six subjects affected by homozygous variants. OBJECTIVE: Patients exhibiting hyperphenylalaninemia in whom deficiencies in hepatic phenylalanine hydroxylase and tetrahydrobiopterin cofactor metabolism had been excluded were subsequently analysed for DNAJC12 variants...

Antigen encounter by T lymphocytes induces important metabolic changes. Anti-tumor T lymphocytes enter in a metabolic competition with tumors, which divert feedback mechanisms of the immune response. Immunosuppressive enzymes, modifying the nutrient availability and leading to the production of toxic catabolites, represent one of these mechanisms, contributing to the metabolic halo in which T lymphocytes evolve during immune responses. Two classes of immunosuppressive enzymes, expressed by the tumor cells or by cells of the microenvironment, have been described: those catabolizing essential or semi-essential amino acids, tryptophan, arginine and phenylalanine and the ectoenzymes, which degrade the ATP to produce adenosine...

The content of the amino acids in the placenta during physiological pregnancy and fetal growth restriction (FGR) has been investigated my means of the method of ion-exchange chromatography. It has been found that in FGR the placental amino acid pool is characterized by a decreased content of arginine, proline, alanine, serine, cysteine, methionine, tryptophan, leucine, threonine, tyrosine, phenylalanine, glutamine and an increased content of dicarboxylic amino acids, lysine, histidine and glycine. These changes are accompanied by altered activity of some enzymes of amino acid metabolism, and the degree of these changes correlates with the level of corresponding amino acids...

Cognitive and mental health problems in individuals with the inherited metabolic disorder phenylketonuria (PKU) have often been associated with metabolic control and its history. For the present study executive functioning (EF) was assessed in 21 PKU patients during childhood (T1, mean age 10.4 years, SD = 2.0) and again in adulthood (T2, mean age 25.8 years, SD = 2.3). At T2 additional assessments of EF in daily life and mental health were performed. Childhood (i.e. 0-12 years) blood phenylalanine was significantly related to cognitive flexibility, executive motor control, EF in daily life and mental health in adulthood (i...

AIM: Childhood cancer remains one of the main cause of death in the pediatric population. Amino acids (AAs) level alterations in plasma are considered to play a role in carcinogenesis and further course of the disease. METHODS: Seventy-seven children with cancer, including 47 with hematological and 30 with solid tumors were enrolled in this study and compared with healthy children. Twenty-two plasma-free AAs were determined by HPLC with fluorometric detection. RESULTS: The results revealed significant decrease in glutamine levels for oncological patients and significant increase in aspartic acid, glutamic acid, asparagine, serine, citrulline, alanine, GABA, tryptophan, methionine, valine, phenylalanine and isoleucine levels in cancer children versus control...

Medical therapy for hereditary hepatorenal tyrosinemia (hereditary tyrosinemia type 1, HT-1) with nitisinone was discovered incidentally, and is a by-product of agrochemistry. It blocks the catabolic pathway of tyrosine, thereby leading to a reduction in the accumulation of toxic metabolites in HT-1. It has to be combined with a low-protein diet supplemented with amino acid mixtures devoid of tyrosine and phenylalanine. This treatment option has completely changed the clinical course of patients suffering from HT-1 who used to die in the first few months to years of life from liver failure, renal dysfunction, and/or hepatocellular carcinoma (HCC)...

Assessment of the liver function, and the need of constant monitoring of the organ's capacity, concerns not only patients with primary liver diseases, but also those at risk of hepatopathies secondary to other chronic diseases. Most commonly, the diagnostics is based on measurements of static biochemical parameters, which allow us to draw conclusions only indirectly about the function and the degree of damage of the organ. On the other hand, liver biopsy is an invasive procedure and therefore it is associated with a considerable risk of complications...

Clinically, Hereditary Tyrosinemia type I (HTI) is especially characterized by severe liver dysfunction in early life. However, recurrent neurological crises are another main finding in these patients when they are treated with a tyrosine and phenylalanine restricted diet only. This is caused by the accumulation of δ-aminolevulinic acid due to the inhibitory effect of succinylacetone on the enzyme that metabolizes δ-aminolevulinic acid. Due to the biochemical and clinical resemblance of these neurological crises and acute intermittent porphyria, this group of symptoms in HTI patients is mostly called porphyria-like-syndrome...

Inborn errors of metabolism (IEMs) are a group of diseases involving a genetic defect that alters a metabolic pathway and that presents usually during infancy. The tyrosine degradation pathway contains five enzymes, four of which being associated with IEMs. The most severe metabolic disorder associated with this catabolic pathway is hereditary tyrosinemia type 1 (HT1; OMIM 276700). HT1 is an autosomal recessive disease caused by a deficiency of fumarylacetoacetate hydrolase (FAH), the last enzyme of the tyrosine catabolic pathway...

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world. It is a type of inflammation-related cancer that usually follows liver hepatitis that mostly caused by hepatitis B virus (HBV) in China. However, the metabolism disturbance of HCC and HBV-cirrhosis is not yet fully understood. In addition, there is little research on the relationships between inflammation mediators and HCC. In this study, we investigated serum metabolic abnormalities in HBV-cirrhosis and HCC patients through non-targeted metabolomics and targeted eicosanoid analysis...

BACKGROUND: Echovirus 30 (E30) causes acute aseptic meningitis. Viral replication requires energy and macromolecular precursors derived from the metabolic network of the host cell. The effect of viral infection within a host cell metabolic activity remains unclear. METHODS: To gain an insight into cell-virus interaction during E30 infection we used a human rhabdomyosarcoma cell line. In a new approach to metabolomics, (1H) NMR was used to measure the level of various cellular metabolites at different times of infection and morphological examination of the cells...

AIM: Phenylketonuria (PKU) is an inborn error of protein metabolism that results from perturbation in phenylalanine hydroxylase activity leading to elevated blood levels of phenylalanine (phe). We aimed to explore the relationships between dietary patterns (total-protein, natural-protein, amino-acid formula), and the ratio of protein to energy intake with growth and body composition. METHOD: Longitudinal prospective data (1-6 measurements) of growth, dietary intake and body composition in patients treated with phe-restricted diet only (D-PKU; n=32), and tetrahydrobiopterin (BH4)±phe-restricted diet (BH4-PKU; n=5) were collected over a two-year period...