Nucleoside

Bài giảng Nucleotide và Acid Nucleic với mục tiêu nắm được khái niệm nucleotid, nucleosid và acid nucleic; cấu tạo và vai trò của nucleotid và acid nucleic.

42p holoesinin 05-06-2014 293 34   Download

Bài giảng "Chương 4: Nucleic acid" trình bày các nội dung: Khái niệm (sơ đồ phân giải nucleic acid, các loại nucleic acid trong tế bào), thành phần hóa học của nucleic acid (đường pentose, các base, nucleoside), cấu tạo (liên kết diestephosphoric, cấu trúc bậc I và bậc II của nucleic acid), sinh tổng hợp nucleic acid (sự nhân đôi của DNA, sự tổng hợp RNA, sự phân giải nucleic acid). Mời các bạn cùng tham khảo.

25p nhansinhaoanh_03 24-10-2015 169 31   Download

Bài giảng Sinh hóa học (Phần I: Sinh hóa học tĩnh): Chương IV nhằm giúp người học phân biệt được cấu tạo của nucleoside, nucleotide và nucleic acid; viết được công thức của ribose, deoxyribose, các base purine, pyrimidine với các dạng enol (lactim) và ketone (lactam) của chúng; viết được cấu tạo và vai trò của một số nucleotide tự do như cAMP, ATP;... Mời các bạn cùng tham khảo chi tiết nội dung bài giảng!

17p andromedashun 18-05-2022 31 2   Download

Luận văn trình bày kết quả nghiên cứu tổng hợp một số cyclobutane nucleoside là dẫn xuất của ribavirin nhằm mục tiêu tìm kiếm các dẫn xuất nucleoside mới có hoạt tính kháng virus, góp phần trong công cuộc đẩy lùi căn bệnh thế kỷ HIV/AIDS và các bệnh do virus gây nên. Mời các bạn tham khảo!

190p generallady 16-07-2021 15 3   Download

Luận văn Thạc sĩ Khoa học: Nghiên cứu thiết lập quy trình định lượng HBV-RNA huyết tương ở bệnh nhân viên gan B mạn tính được thực hiện với mục tiêu nhằm vây dựng và tối ưu quy trình RTqPCR định lượng HBV pgRNA huyết tương với độ nhạy cao trên đối tượng là các bệnh nhân viêm gan B mạn tính đang điều trị bằng các đồng đẳng nucleoside ở Việt Nam. Mời các bạn cùng tham khảo.

93p zhangyan 13-07-2021 30 7   Download

Triomune-30( or -40);Mỗi viên nén chứa: Stavudine 30 mg(or 40 mg); Lamivudine 150 mg; Nevirapine 200 mg.Cả hai stavudine và lamivudine hoạt động bằng cách chấm dứt sự tăng trưởng của các chuỗi DNA và sao chép các ức chế ngược của HIV. Nevirapine là một non-nucleoside ức chế sao chép ngược. Nó hoạt động bằng cách sao chép ngược trực tiếp ức chế. Amantadine: Tác dụng ở giai đoạn 1, tức là ức chế sự hòa nhập virus vào bên trong tế bào ký chủ. Ribavirin: Tác dụng ở giai đoạn 2, tức là ức chế virus (đặc biệt virus cúm) tổng...

44p nhocbuonpkd 26-08-2013 145 25   Download

Guanosine triphosphate nucleotide analogues such as GppNHp (also named GMPPNP) or GTPcS are widely used to stabilize rapidly hydrolyzing protein-nucleotide complexes and to investigate biochemical reaction pathways. Here we describe the chemical synthesis of guanosine 5¢-O-(c-amidotriphosphate) (GTPcNH2) and a new synthesis of guanosine 5¢-O-(c-fluorotriphosphate) (GTPcF). The two nucleotides were characterized using NMR spectroscopy and isothermal titration calorimetry. Chemical shift data on 31P, 19F and 1H NMR resonances are tabulated.

9p system191 01-06-2013 32 5   Download

We previously demonstrated that the major ecto-nucleoside triphosphate phosphohydrolase in the chicken liver membranes is an ecto-ATP-diphosphohydrolase (ectoATPDase) [Caldwell, C., Davis, M.D. & Knowles, A.F. (1999) Arch. Biochem. Biophys. 362, 46–58]. Enzymatic properties of the liver membrane ecto-ATPDase are similar to those of the chicken oviduct ecto-ATPDase that we have previously purified and cloned. Using antibody developed against the latter, we have purified the chicken liver ecto-ATPDase to homogeneity. ...

10p research12 01-06-2013 42 5   Download

Nourseothricins (syn. Streptothricins), agroupof nucleoside peptides produced by several streptomycete strains, contain a polyb-lysine chain of variable length attached in amide linkage to the amino sugar moiety gulosamine of the nucleoside portion. We show that the nourseothricin-pro-ducingStreptomyces nourseicontains an enzyme (NpsA) of an apparentMr56 000 that speci®cally activatesb-lysine by adenylation but does not bind to it as a thioester.

11p research12 29-04-2013 24 4   Download

Substrate properties of xanthine (Xan) and xanthosine (Xao) for purine nucleoside phosphorylases (PNP) of mammalian origin have been reported previously, but only at a single arbitrarily selected pH and with no kinetic con-stants. Additionally, studies have not taken into account the fact that, at physiological pH, Xao (pKa¼5.7) is a mono-anion, while Xan (pKa¼7.7) is an equilibrium mixture of the neutral and monoanionic forms.

10p research12 23-04-2013 41 2   Download

Novel properties of the primer independent synthesis of poly(A), catalyzed by the yeast poly(A) polymerase are presented.The commercial enzyme fromyeast, incontrast to theenzymefromEscherichia coli, is unable to adenylate the 3¢-OH end of nucleosides, nucleotides or dinucleoside poly-phosphates (NpnN).

7p tumor12 22-04-2013 33 3   Download

Pathogenicity ofMycobacterium tuberculosisis closely rela-ted to its ability to survive and replicate in the hostile envi-ronment of macrophages. For some pathogenic bacteria, secretion of ATP-utilizing enzymes into the extracellular environment aids in pathogen survival via P2Z receptor-mediated, ATP-induced death of infected macrophages. A component of these enzymes is nucleoside diphosphate kinase (Ndk). Thendkgenewas cloned fromM. tuberculosis H37Rv and expressed inEscherichia coli.

10p tumor12 20-04-2013 44 4   Download

The multisubstrate deoxyribonucleoside kinase ofDroso-phila melanogaster (Dm-dNK) is sequence-related to three human deoxyribonucleoside kinases and to herpes simplex virus type-1 thymidine kinase. Dm-dNK phos-phorylates both purine and pyrimidine deoxyribonucleo-sides and nucleoside analogues although it has a preference for pyrimidine nucleosides. We performed site-directed mutagenesis on residues that, based on structural data, are involved in substrate recognition.

6p fptmusic 16-04-2013 37 3   Download

Although efficient vaccines are available, chronic hepatitis B (HBV) infection poses a major health problem worldwide, and prolonged treatment of chronicallyinfected HBV patients with nucleoside analogs often results in drug-resistantHBVvariants.Therefore, it is critical toevaluate the contribution of the HBV polymerase to mutations. FLAG-taggedwild-type (FPolE) andmutant (FPolE/D551A)HBV polymerases have been expressed in insect cells and purified. The purified FPolE showed DNA polymerase activity, but FPolE/D551A did not, implying that the activity was derived from FPolE....

8p fptmusic 16-04-2013 41 3   Download

NTPDase1 and NTPDase2 are two related plasma mem-brane-located enzymes involved in the extracellular degra-dation of nucleoside 5¢-tri- and -diphosphates. They differ regarding their hydrolysis ratios for ATP and ADP. Both enzymes have a predicted transmembrane domain close to the N- and C-terminus, respectively, connected by an extensive extracellular domain that carries the active site.We expressed the rat-derived enzymes inXenopus laevisoocytes and analyzed their quarternary structure.

8p fptmusic 16-04-2013 34 5   Download

UMP-CMP kinase catalyses an important step in the phosphorylationofUTP, CTPanddCTP. It is also involved in the necessary phosphorylation by cellular kinases of nucleoside analogs used in antiviral therapies. The reactivity of human UMP-CMP kinase towards natural substrates and nucleotide analogs was reexamined. The expression of the recombinant enzyme and conditions for stability of the enzyme were improved. Substrate inhibition was observed for UMP and CMP at concentrations higher than 0.2 mM, but not for dCMP.

7p fptmusic 16-04-2013 38 3   Download

This article is devoted to the study of redundancy and yield of salvage pathways in human erythrocytes. These cells are not able to synthesize ATPde novo. However, the salvage (recycling) of certain nucleosides or bases to give nucleotide triphosphates is operative. As the salvage pathways use enzymes consuming ATP as well as enzymes producing ATP, it is not easy to see whether a net synthesis of ATP is possible. As for pathways using adenosine, a straightforward assumption is that these pathways start with adenosine kinase....

13p fptmusic 12-04-2013 47 2   Download

The multisubstrate nucleoside kinase of Drosophila melanogaster(Dm-dNK) can be expressed in human solid tumor cells and its unique enzymatic properties makes this enzyme a suicide gene candidate. In the present study,Dm-dNK was stably expressed in the CCRF-CEM and H9 T-lymphoblastoid cell lines. The expressed enzyme was localized to the cell nucleus and the enzyme retained its activity.

11p fptmusic 11-04-2013 41 2   Download

TheDrosophila melanogasterdeoxyribonucleoside kinase (Dm-dNK) double mutant N45D⁄N64D was identified during a previous directed evolution study. This mutant enzyme had a decreased activity towards the natural substrates and decreased feedback inhibition with dTTP, whereas the activ-ity with 3¢-modified nucleoside analogs like 3¢-azidothymidine (AZT) was nearly unchanged.

10p fptmusic 11-04-2013 34 3   Download

The interaction of the homeodomain of the sunflower KNOX protein HAKN1 with DNA was studied by site-directed mutagenesis, hydroxyl radical footprinting and missing nucleoside experiments. Binding of HAKN1 to different oligonucleotides indicated that HAKN1 prefers the sequence TGACA (TGTCA), with changes within the GAC core more pro-foundly affecting the interaction. Footprinting and missing nucleoside experiments using hydroxyl radical cleavage of DNA showed that HAKN1 interacts with a 6-bp region of the strand carrying the GAC core, covering the core and nucleotides towards the 3¢ end....

13p awards 05-04-2013 41 4   Download