Ribonucleotide reductase chemical function

NOS products of neurons, epithelial cells and other cells in the lung have both bronchodilator and inflammatory properties (Gaston etal., 1994b) the specific nature of this bioactivity depends on the chemical characteristics of the functional products in the specific microenvironment under consideration. For example, NO is capable of complexing with and affecting the activity of a variety of metalloproteins and enzymes, such as guanylyl cyclase and ribonucleotide reductase (Nathan, 1992 Stamler et al., 1992). NO can also complex with superoxide anion to form peroxynitrite, which has a cytotoxic immune effector role (Radi etal., 1991 Stamler etal., 1992). Furthermore, NO can form iron nitrosyl complexes, which are the putative intracellular macrophage products of iNOS responsible for lysis of intracellular parasites (Hibbs... 

In addition to the above considerations, one approach to design nucleoside analogues that exert a broad spectrum of activity toward both leukemic and solid tumors has been the construction of analogues that (i) are not substrates for cytidine deaminase, (ii) are converted into the corresponding 5 -polyphosphates by certain kinases, which inhibit ribonucleotide reductase and/or DNA polymerases, and can also be incorporated into a DNA molecule, (iii) have a chemically reactive functionality at the 2 -P position of 2 -deoxycytidine, which is chemically stable at the nucleoside level but would be expected to be reactive after incorporation into a DNA molecule to cleave phosphodiester linkages and/or to produce... 

Chemical ablation is an effective tool for studying nervous system development and function in Drosophila. The only substance currently used for this purpose in flies is hydroxyurea (HU), an inhibitor of ribonucleotide reductase that blocks DNA synthesis and kills... 

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