5' end labeling of tRNA

[Rimantas.Plaipa at lt.VU.GF]

Yes, all problem is in stoichiometry.
      Recessed tRNA 5' end is phosphorylated very slowly by PNK. All
RNA preparations contain some amount of degradation products, most of
them with unpaired 5' end, which react much more rapidly. They are
phosphorylated foremost, wasting ATP. If amount of ATP is too low,
you get only short degradation products labelled.
      You should add as much ATP, as you have 5' ends. If you are
using labelled ATP with high specific activity, add unlabelled ATP.

Rimantas Plaipa

Dept. of Biochem. and Biophys.,Vilnius University,Lithuania,
Rimantas.Plaipa at GF.VU.LT