[Determination of DNA nonradioactively labeled with photobiotin using streptavidin conjugates with peroxidase or alkaline phosphatase].

A sensitive non-radioactive method for detecting biotinylated DNA is described. DNA was biotinylated with photobiotin, then processed by peroxidase and alkaline phosphatase covalently bound to streptavidin in the presence of the substrates of these enzymes. The formation of colored products was observed. The sensitivity of ca. 1.10(-9) g of DNA was achieved by using the conjugate of streptavidin and peroxidase, and that of ca. 1.10(-12) g of DNA--by using the cojugate of streptavidin and alkaline phosphatase. Due to rapidity, reproducibility and sensitivity of the method it can be used as an alternative to radioactive labeling with 32P.