18646-11-2Relevant academic research and scientific papers
Spectroscopic and kinetic studies of interactions of calf spleen purine nucleoside phosphorylase with 8-azaguanine, and its 9-(2-phosphonylmethoxyethyl) derivative
Wierzchowski, Jacek,Stepniak, Katarzyna,Bzowska, Agnieszka,Shugar, David
, p. 459 - 464 (2005)
Spectroscopic and kinetic studies of interactions of calf spleen purine nucleoside phosphorylase with 8-azaguanine, an excellent fluorescent/fluorogenic substrate for the synthetic pathway of the reaction, and its 9-(2-phosphonylmethoxyethyl) derivative, a bisubstrate analogue inhibitor, were carried out. The goal was to clarify the catalytic mechanism of the enzymatic reaction by identification of ionic/tautomeric forms of these ligands in the complex with PNP. Copyright Taylor & Francis, Inc.
Binding of substrates by purine nucleoside phosphorylase (PNP) from Cellulomonas sp. - Kinetic and spectrofluorimetric studies
Wielgus-Kutrowska,Tebbe,Wierzchowski,Shugar,Saenger,Koellner,Bzowska
, p. 871 - 872 (1999)
Dissociation constants and stoichiometry of binding for interaction of Cellulomonas sp. purine nucleoside phosphorylase with its substrates: inosine/guanosine, orthophosphate, guanine/hypoxanthine and D-ribose-1- phosphate were studied by kinetic and spectrofluorimetric methods.
The Peculiar Case of the Hyper-thermostable Pyrimidine Nucleoside Phosphorylase from Thermus thermophilus**
Kaspar, Felix,Neubauer, Peter,Kurreck, Anke
, p. 1385 - 1390 (2021/01/29)
The poor solubility of many nucleosides and nucleobases in aqueous solution demands harsh reaction conditions (base, heat, cosolvent) in nucleoside phosphorylase-catalyzed processes to facilitate substrate loading beyond the low millimolar range. This, in turn, requires enzymes that can withstand these conditions. Herein, we report that the pyrimidine nucleoside phosphorylase from Thermus thermophilus is active over an exceptionally broad pH (4–10), temperature (up to 100 °C) and cosolvent space (up to 80 % (v/v) nonaqueous medium), and displays tremendous stability under harsh reaction conditions with predicted total turnover numbers of more than 106 for various pyrimidine nucleosides. However, its use as a biocatalyst for preparative applications is critically limited due to its inhibition by nucleobases at low concentrations, which is unprecedented among nonspecific pyrimidine nucleoside phosphorylases.
Characterization of pyrimidine nucleoside phosphorylase of Mycoplasma hyorhinis: Implications for the clinical efficacy of nucleoside analogues
Vande Voorde, Johan,Gago, Federico,Vrancken, Kristof,Liekens, Sandra,Balzarini, Jan
experimental part, p. 113 - 123 (2012/10/23)
In the present paper we demonstrate that the cytostatic and antiviral activity of pyrimidine nucleoside analogues is markedly decreased by a Mycoplasma hyorhinis infection and show that the phosphorolytic activity of the mycoplasmas is responsible for this. Since mycoplasmas are (i) an important cause of secondary infections in immunocompromised (e.g. HIV infected) patients and (ii) known to preferentially colonize tumour tissue in cancer patients, catabolic mycoplasma enzymesmay compromise efficient chemotherapy of virus infections and cancer. In the genome of M. hyorhinis, a TP (thymidine phosphorylase) gene has been annotated. This gene was cloned, expressed in Escherichia coli and kinetically characterized. Whereas the mycoplasma TP efficiently catalyses the phosphorolysis of thymidine (Km = 473 μM) and deoxyuridine (Km = 578 μM), it prefers uridine (K m =92 μM) as a substrate. Our kinetic data and sequence analysis revealed that the annotated M. hyorhinis TP belongs to the NP (nucleoside phosphorylase)-II class PyNPs (pyrimidine NPs), and is distinct from the NP-II class TP and NPI class UPs (uridine phosphorylases). M. hyorhinis PyNP also markedly differs from TP and UP in its substrate specificity towards therapeutic nucleoside analogues and susceptibility to clinically relevant drugs. Several kinetic properties of mycoplasma PyNP were explained by in silico analyses. The Authors Journal compilation
Transition-state analysis of Trypanosoma cruzi uridine phosphorylase- catalyzed arsenolysis of uridine
Silva, Rafael G.,Vetticatt, Mathew J.,Merino, Emilio F.,Cassera, Maria B.,Schramm, Vern L.
experimental part, p. 9923 - 9931 (2011/08/10)
Uridine phosphorylase catalyzes the reversible phosphorolysis of uridine and 2′-deoxyuridine to generate uracil and (2-deoxy)ribose 1-phosphate, an important step in the pyrimidine salvage pathway. The coding sequence annotated as a putative nucleoside phosphorylase in the Trypanosoma cruzi genome was overexpressed in Escherichia coli, purified to homogeneity, and shown to be a homodimeric uridine phosphorylase, with similar specificity for uridine and 2′-deoxyuridine and undetectable activity toward thymidine and purine nucleosides. Competitive kinetic isotope effects (KIEs) were measured and corrected for a forward commitment factor using arsenate as the nucleophile. The intrinsic KIEs are: 1′-14C = 1.103, 1,3-15N 2 = 1.034, 3-15N = 1.004, 1-15N = 1.030, 1′-3H = 1.132, 2′-2H = 1.086, and 5′-3H2 = 1.041 for this reaction. Density functional theory was employed to quantitatively interpret the KIEs in terms of transition-state structure and geometry. Matching of experimental KIEs to proposed transition-state structures suggests an almost synchronous, S N2-like transition-state model, in which the ribosyl moiety possesses significant bond order to both nucleophile and leaving groups. Natural bond orbital analysis allowed a comparison of the charge distribution pattern between the ground-state and the transition-state models.
Biosynthetic origin and mechanism of formation of the aminoribosyl moiety of peptidyl nucleoside antibiotics
Chi, Xiuling,Pahari, Pallab,Nonaka, Koichi,Van Lanen, Steven G.
supporting information; experimental part, p. 14452 - 14459 (2011/11/04)
Several peptidyl nucleoside antibiotics that inhibit bacterial translocase I involved in peptidoglycan cell wall biosynthesis contain an aminoribosyl moiety, an unusual sugar appendage in natural products. We present here the delineation of the biosynthetic pathway for this moiety upon in vitro characterization of four enzymes (LipM-P) that are functionally assigned as (i) LipO, an l-methionine:uridine-5′-aldehyde aminotransferase; (ii) LipP, a 5′-amino-5′-deoxyuridine phosphorylase; (iii) LipM, a UTP:5-amino-5-deoxy-α-d-ribose-1-phosphate uridylyltransferase; and (iv) LipN, a 5-amino-5-deoxyribosyltransferase. The cumulative results reveal a unique ribosylation pathway that is highlighted by, among other features, uridine-5′-monophosphate as the source of the sugar, a phosphorylase strategy to generate a sugar-1-phosphate, and a primary amine-requiring nucleotidylyltransferase that generates the NDP-sugar donor.
N6-acetyl-2,3,5-tri-O-acetyladenosine; A convenient, missed out substrate for regioselective N6-alkylations
Tararov, Vitali I.,Kolyachkina, Svetlana V.,Alexeev, Cyril S.,Mikhailov, Sergey N.
experimental part, p. 2483 - 2489 (2011/09/20)
A simple and efficient route to N6-acetyl-2,3,5-tri-O- acetyladenosine (1) was developed based on selective N-deacetylation of pentaacetylated adenosine 2 with methanol at room temperature in the presence of imidazole. Preparative synthesis of 1 was elaborated utilizing a crude mixture of 2 and 1 which is produced by reaction of adenosine with acetic anhydride in pyridine at elevated temperatures. The total yield of 1 was 80-85% starting with adenosine. It was shown that 1 is a convenient substrate for selective N 6-alkylations. The study revealed the same regioselectivity in base-promoted reactions of 1 with activated alkyl halides and Mitsunobu reactions of 1 with alcohols. A series of N6-alkyladenosines 5a-f were prepared. Cytokinins 6b,d,e were prepared by enzymatic transformation of parent nucleoside derivatives 5b,d,e using a combination of nucleoside phosphorylase and alkaline phosphatase. Georg Thieme Verlag Stuttgart, New York.
Kinetic properties of Cellulomonas sp. purine nucleoside phosphorylase with typical and non-typical substrates: Implications for the reaction mechanism
Wielgus-Kutrowska, Beata,Bzowska, Agnieszka
, p. 471 - 476 (2008/02/01)
Phosphorolysis catalyzed by Cellulomonas sp. PNP with typical nucleoside substrate, inosine (Ino), and non-typical 7-methylguanosine (m7Guo), with either nucleoside or phosphate (Pi) as the varied substrate, kinetics of the reverse synthetic reaction with guanine (Gua) and ribose-1-phosphate (R1P) as the varied substrates, and product inhibition patterns of synthetic and phosphorolytic reaction pathways were studied by steady-state kinetic methods. It is concluded that, like for mammalian trimeric PNP, complex kinetic characteristics observed for Cellulomonas enzyme results from simultaneous occurrence of three phenomena. These are sequential but random, not ordered binding of substrates, tight binding of me substrate purine bases, leading to the circumstances that for such substrates (products) rapid-equilibrium assumptions do not hold, and a dual role of Pi, a substrate, and also a reaction modifier that helps to release a tightly bound purine base. Copyright Taylor & Francis, Inc.
Gene therapy of cancer: activation of nucleoside prodrugs with e. colipurine nucleoside phosphorylase
Secrist III, John A.
, p. 745 - 757 (2007/10/03)
During the last few years, many gene therapy strategies have been developed for various disease targets. The development of anticancer gene therapy strategies to selectively generate cytotoxic nucleoside or nucleotide analogs is an attractive goal. One such approach involves the delivery of herpes simplex virus thymidine kinase followed by the acyclic nucleoside analog ganciclovir. We have developed another gene therapy methodology for the treatment of cancer that has several significant attributes. Specifically, our approach involves the delivery of E. coli purine nucleoside phosphorylase, followed by treatment with a relatively non-toxic nucleoside prodrug that is cleaved by the enzyme to a toxic compound. .This presentation describes the concept, details our search for suitable prodrugs, and summarizes the current biological data. Copyright
Reversible and in Situ Formation of Organic Arsenates and Vanadates as Organic Phosphate Mimics in Enzymatic Reactions: Mechanistic Investigation of Aldol Reactions and Synthetic Applications
Drueckhammer, Dale G.,Durrwachter, J. Robert,Pederson, Richard L.,Crans, Debbie C.,Daniels, Lacy,Wong, Chi-Huey
, p. 70 - 77 (2007/10/02)
A synthetic strategy is developed that uses organic phosphate utilizing enzymes as catalysts and a mixture of an organic alcohol and inorganic arsenate or vanadate to replace the organic phosphate substrate.In this process, inorganic arsenate or vanadate reacts with the alcohol reversibly in situ to form a mixture of esters, one of which is accepted by the enzyme as a substrate.Examples of the utility of this approach are demonstrated in enzymatic aldol condensations catalyzed by fructose-1,6-diphosphate aldolase, fuculose-1-phosphate aldolase, and rhamnulose-1-phosphate aldolase with a mixture of dihydroxyacetone and inorganic arsenate as substrate.Several uncommon sugars and deoxy sugars are prepared on 5-17-mmol scales.Mechanistic studies on an aldol reaction indicate that the redox reaction between dihydroxyacetone and inorganic vanadate prohibits the use of such a mixture to replace dihydroxyacetone phosphate in enzymatic aldol condensations.
