Nucleic adds introduction

Watanabe, S. and Ueda, T.. Introduction of substituents to the 7(8)-posilion of 7-deazaa-denosine (lubercidin) convereion to toyoca-myem. Nucleic Adds Symp. Sen. 8,21, 1980 Chem. Ahstr., 94, 175411, 1981. 

Introduction and Rationale. DHFR is an ideal system to study for a number of reasons. The catalytic properties of DHFR are such that under normal physiologic conditions and with the NADPH cofactor bound, 7,8-dihydrofolate (DHF) is reduced to 5,6,7,8-tetrahydrofolate (THF) (7). Thus DHFR plays an important role in cell metabolism by maintaining a supply of THF. THF is used by the cell as both a cofactor and in substrate quantities in the synthesis of deoxythymidine. By inhibiting the production of THF, deoxythymidine synthesis is curtailed, nucleic add replication comes to a halt, and cell proliferation ceases. It is this biochemical cascade which supplies the pharmacological and chemotherapeutic applications of inhibitors to DHFR. 

Introduction to Nucleic Add Synthesis Never-Ending Quest for Excellence... 

Further performance improvements in analysing nucleic acids could be achieved by the introduction of 3-hydroxypicolinic add as matrix [8] and the introduction of delayed extraction in a linear time-of-flight mass spectrometer [9]. If, for MALDI Fourier transform mass spectrometry, the molecular weight range in analysing nucleic add fragments could be extended further this type of MALDI MS would become of significant value due to the extraordinary resolution possible [10, 11]. In order to reach the sensitivity level necessary for MALDI-TOF MS analysis an amplification step has to be incorporated into the sample preparation process for... 

Nucleic acid (Introduction, Chapter 28) A biopolymer containing three types of monomer units heterocyclic aromatic amine bases derived from purine and pyrimidine, the monosaccharides D-ribose or 2-deoxy-D-iibose, and phosphoric add. 

Chemical shifts (cs) are expressed in parts per million (ppm) downiield from a chosen reference signal of an added internal standard compound. Any of three different standard compounds are commonly employed to measure the proton shifts of nucleic adds in H2O or DjO solution DSS, TSP or TMA (see section 3.5.4.2). The frequency of the methyl protons of DSS and TSP (at pH 7) are hoth close to, but not identical with, the frequency of the common standard tetramethylsilane (TMS), employed in non-aqueous solvents. However, TSP is known to display a readfly measurable pH dependence [77D1]. The introduction of TMA followed a report [73L1] in which it was shown that the resonance position of DSS varied with the purine concentration. The central peak of the TMA signal is usually taken to resonate 3.18 ppm dowtfield from DSS. Since the exact shift difference tma dss depend upon various factors (purine concentration, temperature, ionic strength a conversion of one standard to another was not attempted in the present compilation. 

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