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https://www.readbyqxmd.com/read/27815627/association-studies-to-transporting-proteins-of-fac-re-i-co-3-pterin-h2o-complex
#1
Fabricio Ragone, Héctor H Martínez Saavedra, Pablo F García, Ezequiel Wolcan, Gerardo A Argüello, Gustavo T Ruiz
A new synthetic route to acquire the water soluble complex fac-Re(I)(CO)3(pterin)(H2O) was carried out in aqueous solution. The complex has been obtained with success via the fac-[Re(I)(CO)3(H2O)3]Cl precursor complex. Re(I)(CO)3(pterin)(H2O) has been found to bind strongly with bovine and human serum albumins (BSA and HSA) with intrinsic-binding constants, Kb, of 6.5 × 10(5) M(-1) and 5.6 × 10(5) M(-1) at 310 K, respectively. The interactions of serum albumins with Re(I)(CO)3(pterin)(H2O) were evaluated employing UV-vis fluorescence and absorption spectroscopy and circular dichroism...
November 4, 2016: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/27808347/clinical-efficacy-of-melittin-in-the-treatment-of-cats-infected-with-the-feline-immunodeficiency-virus
#2
Anja D Hartmann, Natalie Wilhelm, Volker Erfle, Katrin Hartmann
OBJECTIVE: The bee venom melittin shows an antiviral efficacy against the human immunodeficiency virus in cell culture. It was shown to be non-toxic for cats. Aim of this pilot study was to investigate the clinical efficacy and side-effects of melittin in cats naturally infected with feline immunodeficiency virus (FIV). MATERIAL AND METHODS: The study was performed as a prospective, placebo-controlled double-blinded trial. Twenty cats were included, of which 10 cats each were treated with either melittin (500 µg/kg body weight) or phosphate-buffered saline (placebo) subcutaneously twice per week...
November 3, 2016: Tierärztliche Praxis. Ausgabe K, Kleintiere/Heimtiere
https://www.readbyqxmd.com/read/27693864/acanthamoeba-and-dictyostelium-use-different-foraging-strategies
#3
Nick A Kuburich, Nirakar Adhikari, Jeffrey A Hadwiger
Amoeba often use cell movement as a mechanism to find food, such as bacteria, in their environment. The chemotactic movement of the soil amoeba Dictyostelium to folate or other pterin compounds released by bacteria is a well-documented foraging mechanism. Acanthamoeba can also feed on bacteria but relatively little is known about the mechanism(s) by which this amoeba locates bacteria. Acanthamoeba movement in the presence of folate or bacteria was analyzed in above agar assays and compared to that observed for Dictyostelium...
September 6, 2016: Protist
https://www.readbyqxmd.com/read/27693843/degradation-of-tyrosine-and-tryptophan-residues-of-peptides-by-type-i-photosensitized-oxidation
#4
Carolina Castaño, Mariana Vignoni, Patricia Vicendo, Esther Oliveros, Andrés H Thomas
Pterin derivatives are involved in various biological functions, including enzymatic processes that take place in human skin. Unconjugated oxidized pterins are efficient photosensitizers under UV-A irradiation and accumulate in the skin of patients suffering from vitiligo, a chronic depigmentation disorder. These compounds are able to photoinduce the oxidation of the peptide α-melanocyte-stimulating hormone (α-MSH), which stimulates the production and release of melanin by melanocytes in skin and hair. In the present work we have used two peptides in which the amino acid sequence of α-MSH was mutated to specifically investigate the reactivity of tryptophan (Trp) and tyrosine residues (Tyr)...
September 16, 2016: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/27666634/pterin-7-carboxamides-as-a-new-class-of-aldose-reductase-inhibitors
#5
Ryota Saito, Saori Suzuki, Kaname Sasaki
Aldose reductase is related to the onset and progression of diabetic complications, such as neuropathy, retinopathy, angiopathy, and so on: therefore molecules that are capable of inhibiting the enzyme are potential drugs for treatment of diabetic complications. Epalrestat is the sole aldose reductase inhibitor that is clinically used, but still has some drawbacks. Thus, the development of new aldose reductase inhibitors is still desired. We have synthesized a series of new pterin-7-carboxamides, and evaluated their in vitro inhibitory activities against human aldose reductase...
October 15, 2016: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/27537049/xanthine-dehydrogenase-an-old-enzyme-with-new-knowledge-and-prospects
#6
Cheng-Hua Wang, Chong Zhang, Xin-Hui Xing
Xanthine dehydrogenase (EC 1.17.1.4, XDH) is a typical and complex molybdenum-containing flavoprotein which has been extensively studied for over 110 years. This enzyme catalyzes the oxidation of purines, pterin and aldehydes with NAD(+) or NADP(+) as electron acceptor, and sometimes can be transformed to xanthine oxidase (EC 1.17.3.2, XOD) capable of utilizing oxygen as the electron acceptor. XDHs are widely distributed in all eukarya, bacteria and archaea domains, and are proposed to play significant roles in various cellular processes, including purine catabolism and production of reactive oxygen species (ROS) and nitric oxide (NO) in both physiological and pathological contexts...
August 18, 2016: Bioengineered
https://www.readbyqxmd.com/read/27500308/photooxidation-of-tryptophan-and-tyrosine-residues-in-human-serum-albumin-sensitized-by-pterin-a-model-for-globular-protein-photodamage-in-skin
#7
Lara O Reid, Ernesto A Roman, Andrés H Thomas, M Laura Dántola
Human serum albumin (HSA) is the most abundant protein in the circulatory system. Oxidized albumin was identified in the skin of patients suffering from vitiligo, a depigmentation disorder in which the protection against ultraviolet (UV) radiation fails because of the lack of melanin. Oxidized pterins, efficient photosensitizers under UV-A irradiation, accumulate in the skin affected by vitiligo. In this work, we have investigated the ability of pterin (Ptr), the parent compound of oxidized pterins, to induce structural and chemical changes in HSA under UV-A irradiation...
August 30, 2016: Biochemistry
https://www.readbyqxmd.com/read/27432259/chemical-systems-modeling-the-d-1-mo-v-states-of-molybdenum-enzymes
#8
Charles G Young
This review focuses on the synthesis, properties and electron paramagnetic resonance (EPR), electron spin echo envelope modulation (ESEEM) and electron-nuclear double resonance (ENDOR) spectroscopy of mononuclear d(1) oxo- and sulfido-Mo(V) complexes relevant to the understanding of the EPR-active Mo(V) forms of pterin-containing molybdenum enzymes.
June 4, 2016: Journal of Inorganic Biochemistry
https://www.readbyqxmd.com/read/27423480/pterin-sulfa-conjugates-as-dihydropteroate-synthase-inhibitors-and-antibacterial-agents
#9
Ying Zhao, William R Shadrick, Miranda J Wallace, Yinan Wu, Elizabeth C Griffith, Jianjun Qi, Mi-Kyung Yun, Stephen W White, Richard E Lee
The sulfonamide class of antibiotics has been in continuous use for over 70years. They are thought to act by directly inhibiting dihydropteroate synthase (DHPS), and also acting as prodrugs that sequester pterin pools by forming dead end pterin-sulfonamide conjugates. In this study, eight pterin-sulfonamide conjugates were synthesized using a novel synthetic strategy and their biochemical and microbiological properties were investigated. The conjugates were shown to competitively inhibit DHPS, and inhibition was enhanced by the presence of pyrophosphate that is crucial to catalysis and is known to promote an ordering of the DHPS active site...
August 15, 2016: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/27403587/mechanistic-insights-into-c-h-oxidations-by-ruthenium-iii-pterin-complexes-impact-of-basicity-of-the-pterin-ligand-and-electron-acceptability-of-the-metal-center-on-the-transition-states
#10
Hiroumi Mitome, Tomoya Ishizuka, Hiroaki Kotani, Yoshihito Shiota, Kazunari Yoshizawa, Takahiko Kojima
A ruthenium(II) complex, [Ru(dmdmp)Cl(MeBPA)] (2) (Hdmdmp = N,N-dimethyl-6,7-dimethylpterin, MeBPA = N-methyl-N,N-bis(pyridylmethyl)amine), having a pterin derivative as a proton-accepting ligand, was synthesized and characterized. Complex 2 shows higher basicity than that of a previously reported Ru(II)-pterin complex, [Ru(dmdmp) (TPA)](+) (1) (TPA = tris(2-pyridylmethyl)amine). On the other hand, 1e(-)-oxidized species of 1 (1OX) exhibits higher electron-acceptability than that of 1e(-)-oxidized 2 (2OX). Bond dissociation enthalpies (BDE) of the two Ru(II) complexes having Hdmdmp as a ligand in proton-coupled electron transfer (PCET) to generate 1OX and 2OX were calculated to be 85 kcal mol(-1) for 1OX and 78 kcal mol(-1) for 2OX...
August 3, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27296228/photosensitized-reactions-initiated-by-6-carboxypterin-singlet-and-triplet-reactivity
#11
L Tinel, S Rossignol, R Ciuraru, S Dumas, C George
Pterins, derivatives of 2-aminopteridin-4(3H)-one, are natural photosensitizers, common to many biological systems. Indications that these photosensitizers are also present in the sea-surface microlayer motivated the study of the photophysical and photochemical properties of 6-carboxypterin (CPT), which was chosen as a model for this group of photoactive compounds. The kinetics of excited CPT in the singlet and triplet state in the presence of halides and organics were studied in aqueous solutions at neutral pH by means of steady-state fluorescence and laser-flash photolysis...
June 22, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27272191/erratum-to-lc-ms-ms-analysis-of-cerebrospinal-fluid-metabolites-in-the-pterin-biosynthetic-pathway
#12
Erland Arning, Teodoro Bottiglieri
No abstract text is available yet for this article.
June 8, 2016: JIMD Reports
https://www.readbyqxmd.com/read/27246466/four-years-of-diagnostic-challenges-with-tetrahydrobiopterin-deficiencies-in-iranian-patients
#13
Shohreh Khatami, Soghra Rouhi Dehnabeh, Sirous Zeinali, Beat Thöny, Mohammadreza Alaei, Shadab Salehpour, Aria Setoodeh, Farzaneh Rohani, Fatemeh Hajivalizadeh, Ashraf Samavat
Hyperphenylalaninemia (HPA) is a condition caused by tetrahydrobiopterin (BH4) and phenylalanine hydroxylase (PAH) deficiencies. It is essential that differential diagnosis be conducted to distinguish these two causes of HPA, because BH4 deficiency is a more severe disease involving progressive neurologic deterioration. Based on the biological findings, HPA is defined as a plasma phenylalanine level of >2.0 mg/dl (>120 μmol/l). The National Biochemistry Reference Laboratory at the Pasteur Institute of Iran initiated BH4 deficiency screening tests for the first time during the implementation of a nationwide phenylketonuria (PKU) screening program...
June 1, 2016: JIMD Reports
https://www.readbyqxmd.com/read/27246263/role-and-expression-of-cry1-in-the-adductor-muscle-of-the-oyster-crassostrea-gigas-during-daily-and-tidal-valve-activity-rhythms
#14
Audrey M Mat, Mickael Perrigault, Jean-Charles Massabuau, Damien Tran
Cryptochromes are flavin- and pterin-containing photoreceptors of the cryptochrome/photolyase family. They play critical roles in organisms, among are which light-dependent and light-independent roles in biological rhythms. The present work aimed at describing a cryptochrome gene in the oyster Crassostrea gigas by (i) a characterization and phylogenetic analysis and (ii) by studying its expression in the relationship to rhythmic valve behavior in different entrainment regimes. Cryptochrome expression was focused on the adductor muscle of the oyster, the effector of the valve behavior...
2016: Chronobiology International
https://www.readbyqxmd.com/read/27222084/-autosomal-recessive-gtpch-1-deficiency-the-importance-of-the-analysis-of-neurotransmitters-in-cerebrospinal-fluid
#15
E E Moreno-Medinilla, M D Mora-Ramirez, R Calvo-Medina, J Martinez-Anton
INTRODUCTION: A deficiency of the enzyme guanosine triphosphate cyclohydrolase I (GTPCH 1) causes a reduction in the synthesis of tetrahydrobiopterin (BH4), a cofactor that is essential in the synthesis of tyrosine, dopamine and serotonin. It is an infrequent disease that produces psychomotor delay or regression and movement disorders, although treatment can improve or even correct the clinical signs and symptoms. CASE REPORT: We report the case of a girl with autosomal recessive GTPCH deficiency, who was diagnosed at 14 months by means of an analysis of the cerebrospinal fluid with pterin, HVA and 5-HIAA deficiency, and positive phenylalanine overload test and genetic study...
June 1, 2016: Revista de Neurologia
https://www.readbyqxmd.com/read/27216311/a-quantitative-structure-property-relationship-qspr-study-of-singlet-oxygen-generation-by-pteridines
#16
Andrey A Buglak, Taisiya A Telegina, Mikhail S Kritsky
The QSPR method is used in photochemistry for the prediction of the absorption wavelength, fluorescence intensity, photolysis quantum yield, etc. However, to our knowledge, no attempts have been made to use the quantum yield of singlet oxygen ((1)O2) generation (ΦΔ) as an analyzed parameter in a QSPR study. We performed QSPR analysis of 29 pteridine compounds (including pterin and flavin sensitizers) for their ability to produce singlet oxygen in aqueous (D2O) solutions. Pteridines are ubiquitously present in living systems (mostly as coenzymes), possess high photochemical activity and have multiple applications as photosensitizers...
June 8, 2016: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/27154982/thymidine-radical-formation-via-one-electron-transfer-oxidation-photoinduced-by-pterin-mechanism-and-products-characterization
#17
Mariana P Serrano, Mariana Vignoni, Carolina Lorente, Patricia Vicendo, Esther Oliveros, Andrés H Thomas
UV-A radiation (320-400nm), recognized as a class I carcinogen, induces damage to the DNA molecule and its components through different mechanisms. Pterin derivatives are involved in various biological functions, including enzymatic processes, and it has been demonstrated that oxidized pterins may act as photosensitizers. In particular, they accumulate in the skin of patients suffering from vitiligo, a chronic depigmentation disorder. We have investigated the ability of pterin (Ptr), the parent compound of oxidized pterins, to photosensitize the degradation of the pyrimidine nucleotide thymidine 5'-monophosphate (dTMP) in aqueous solutions under UV-A irradiation...
July 2016: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/27145334/domain-movements-upon-activation-of-phenylalanine-hydroxylase-characterized-by-crystallography-and-chromatography-coupled-small-angle-x-ray-scattering
#18
Steve P Meisburger, Alexander B Taylor, Crystal A Khan, Shengnan Zhang, Paul F Fitzpatrick, Nozomi Ando
Mammalian phenylalanine hydroxylase (PheH) is an allosteric enzyme that catalyzes the first step in the catabolism of the amino acid phenylalanine. Following allosteric activation by high phenylalanine levels, the enzyme catalyzes the pterin-dependent conversion of phenylalanine to tyrosine. Inability to control elevated phenylalanine levels in the blood leads to increased risk of mental disabilities commonly associated with the inherited metabolic disorder, phenylketonuria. Although extensively studied, structural changes associated with allosteric activation in mammalian PheH have been elusive...
May 25, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27094187/characterization-of-unexplored-amidohydrolase-enzyme-pterin-deaminase
#19
REVIEW
Angayarkanni Jayaraman, Murugesan Thandeeswaran, Ulaganathan Priyadarsini, Shanmugam Sabarathinam, K A Ayub Nawaz, Muthusamy Palaniswamy
Pterin deaminase is an amidohydrolase enzyme hydrolyzing pteridines to form lumazine derivatives and ammonia. The enzyme captured the attention of scientists as early as 1959 and had been patented for its application as an anticancer agent. It is ubiquitously present in prokaryotes and has been reported in some eukaryotes such as honey bee, silkworm and rats. The enzyme has been observed to have a spectrum of substrates with the formation of respective lumazines. The role of the substrates of the enzyme in various metabolic pathways warrants a significant role in the biological activity of both prokaryotes and eukaryotes...
June 2016: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/27065985/experimental-and-metabolic-modeling-evidence-for-a-folate-cleaving-side-activity-of-ketopantoate-hydroxymethyltransferase-panb
#20
Jennifer J Thiaville, Océane Frelin, Carolina García-Salinas, Katherine Harrison, Ghulam Hasnain, Nicole A Horenstein, Rocio I Díaz de la Garza, Christopher S Henry, Andrew D Hanson, Valérie de Crécy-Lagard
Tetrahydrofolate (THF) and its one-carbon derivatives, collectively termed folates, are essential cofactors, but are inherently unstable. While it is clear that chemical oxidation can cleave folates or damage their pterin precursors, very little is known about enzymatic damage to these molecules or about whether the folate biosynthesis pathway responds adaptively to damage to its end-products. The presence of a duplication of the gene encoding the folate biosynthesis enzyme 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (FolK) in many sequenced bacterial genomes combined with a strong chromosomal clustering of the folK gene with panB, encoding the 5,10-methylene-THF-dependent enzyme ketopantoate hydroxymethyltransferase, led us to infer that PanB has a side activity that cleaves 5,10-methylene-THF, yielding a pterin product that is recycled by FolK...
2016: Frontiers in Microbiology
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