Dideoxynucleotide

The absence of the 3' hydroxyl group inhibits this nucleophilic attack from happening, disabling the DNA polymerase's ability to continue with its function.

Thus, these molecules form the basis of the dideoxy chain-termination method of DNA sequencing, which was reported by Frederick Sanger and his team in 1977[3] as an extension of earlier work.

"[1] Sanger won his second Nobel Prize in Chemistry in 1980, sharing it with Walter Gilbert ("for their contributions concerning the determination of base sequences in nucleic acids") and with Paul Berg ("for his fundamental studies of the biochemistry of nucleic acids, with particular regard to recombinant DNA"),[6] and discussed the use of dideoxynucleotides in his Nobel lecture.

After stirring at room temperature for 24 hours, the reaction mixture was poured into an aqueous sodium bicarbonate solution followed by extraction with chloroform 5 times.

This product example is then hydrated to remove the double bond through dissolving it in methanol (10 ml) containing a catalyst (wet 5% palladium on carbon) (400 mg) in an atmosphere of hydrogen for 1 h to obtain the resultant dideoxynucleoside ( 2',3'-dideoxyuridine in this case).

It is possible that immediate reaction with the dye may also occur, but extending the arm is claimed to increase efficiency in the case of using a mutant form of DNA polymerase.