Methyltransferase Assay. 
Set up the assays, to contain 50.0 µL total per assay with 3 µg of DNA and 2 µCi of Adenosyl-L-Methionine, S-Methyl (3H), and the enzyme to be tested.
Incubate the assays at 37°C for 2 hours.
Add 30 µL (60 µg) of proteinase K to each assay.
Incubate at 65°C for 20 min.
Add 4 µL (20 µg) of ss salmon sperm DNA as a carrier.
Add an equal volume (84 µL) of 20% TCA and incubate at 4°C for 10 min to precipitate the samples.
Centrifuge the assays in the microfuge for 5 min at 4°C.
Discard the supernatants.
Wash the pellets 2X with 200 µL of 5% TCA in the microfuge for 5 min at 4°C.
Resuspend the pellets with 500 µL each of 500 mM NaOH.
Incubate the assays at 65°C for 20 min.
Precipitate the samples with 500 µL of 20% TCA for 10 min at 4°C.
Centrifuge the samples in the microfuge for 5 min at 4°C.
Wash the pellets 2X with 200 µL of 5% TCA in the microfuge for 5 min at 4°C.
Resuspend the pellet with 500 µL of 5% TCA.
Incubate in boiling water for 30 min (loosen the caps or puncture the caps of the tubes).
Centrifuge the samples in the microfuge for 5 min at 4°C to remove the insoluble material.
Count the supernatants in 10 mL of triton-toluene counting solution.
