the time constant for dissociation of actinomycin d from the agct site was 2900 sec as measured by an in vitro transcription assay at 37 degrees , and suggests that , under conditions of active transcription of the dna , the drug-dna complex has additional stabilising contributions , possibly by a cage effect from rna polymerase , or by additional drug-rna polymerase contacts .
C0040649
transcription
C0035681
rna polymerase