Nucleic acid labeling compounds including the following structure are disclosed:
wherein A is a triphosphate group with apporpriate counterions, said counterions selected from the group consisting of H+, Na+, Li+, K+, and NH
4
+; X is O; Y is OH; Z is OH; L is selected from the group consisting of —CH═CH—C(O)—NH—CH
2
—CH
2
—NH—C(O)— and —CH
2
—CH
2
—C(O)—NH—CH
2
—CH
2
—NH—C(O); M is —(CH
2
)
45
—NH—, n is 1 and Q is biotin having the structure:
The labeling compounds are suitable for enzymatic attachment to a nucleic acid, either terminally or internally, to provide a mechanism of nucleic acid detection.