Deoxyribonucleotide triphosphates

Fluorescein-labelled deoxyribonucleotide triphosphates may be used in place of those labelled with 32P. Once the DNA sequences are separated by electrophoresis, the resulting DNA bands fluoresce and are analysed by a flu-orogram imager, which produces a picture of the fluorescent bands similar to the autoradiography produced when using 32P-labelled nucleotides. 

ALL, acute lymphoblastic leukemia AML, acute myelogenous leukemia CLL, chronic lymphocytic leukemia CML, chronic myelogenous leukemia DHFR, dihydrofolate reductase dNTP, deoxyribonucleotide triphosphate FdUTP, 5-fluorodeoxyuridine-5 -triphosphate FUTP, 5-fluorouridine-5 -triphosphate TS, thymidine synthase. 

UTP, and CTP are needed for RNA synthesis and the 2 -deoxyribonucleotide triphosphates, dATP, dTTP, dGTP, and dCTP for DNA synthesis. In every case, the addition of activated monomer units to a growing polynucleotide chain is catalyzed by an enzyme that... 

Many of the enzymes participating in de novo synthesis of deoxyribonucleotide triphosphates, as well as those responsible for interconversion of deoxyribonucleotides, increase in activity when cells prepare for DNA synthesis. The need for increased DNA synthesis occurs under three circumstances (1) when the cell proceeds from the G0, or resting, stage of the cell cycle to the S, or synthetic or replication, stage (fig. 23.26) (2) when it performs repair after extensive DNA damage and (3) after infection of quiescent cells with virus. When cells leave G0, for example, enzymes such as thymidylate synthase and ribonucleotide reductase, increase as well as the corresponding mRNAs. These increases in enzyme amount supplement allosteric controls that increase the activity of each enzyme molecule. Corresponding decreases in amounts of these enzymes and their mRNAs occur when DNA synthesis is completed. 

DNA polymerase. An enzyme that catalyzes the formation of 3 -5 phospho-diester bonds from deoxyribonucleotide triphosphates. 

Reverse transcriptase. An enzyme that synthesizes DNA from an RNA template, using deoxyribonucleotide triphosphates. 

Four deoxyribonucleotide triphosphates (dNTP s) are required for DNA synthesis (note the only difference between deoxyribonucleotides and ribonucleotides is the absence of an OH group at position 2 on the ribose ring). These are dATP, dGTP, dTTP and dCTP. The high energy phosphate bond between the a and (3 phosphates is cleaved and the deoxynucleotide monophosphate is incorporated into the new DNA strand. 

Convert mRNAs to cDNAs by reverse transcriptase, using fluorescently labeled deoxyribonucleotide triphosphates. 

The reactants are deoxyribonucleotide triphosphates. They provide not only the moiety to be inserted (the deoxyribonucleotide) but also the energy to drive the reaction (dNTP inserted NMP + PP., PP. 2Pj). 

They check the size of an incoming deoxyribonucleotide triphosphate (dNTP) to help insure that the correct, complementary choice is made. 

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