The synthesis of 2'-deoxycytidine triphosphate carrying mercaptoethyl group
s at position 4 of cytosine is described. This nucleoside triphosphate was
reacted with a maleimido-peptide carrying the c-mye tag-sequence to yield a
peptide-nucleoside triphosphate chimera. Primer extension studies showed t
hat the nucleoside triphosphate modified with the peptide sequence is incor
porated by DNA polymerases opposite guanine.