title: Inhibition of poly(A) polymerase by rifamycin derivatives.
abstract: The effect of several rifamycin derivatives on poly(A) synthesis in vitro was tested using purified rat liver mitochondrial poly(A) polymerase assayed with an exogenous primer. When used at a concentration of 300 mug/ml, derivatives AF/013, PR/19, AF/AETP, M/88 and AF/ABDP completely inhibited activity corresponding to 50 mug of enzyme protein. Under similar conditions, derivatives DMAO and AF/MO failed to inhibit enzyme activity. Studies with PR/19 showed that the drug interacted directly with the enzyme molecule and did not affect the enzyme-primer complex formation. The inhibition by the drug could be reversed by increasing the substrate (ATP) concentration. It is concluded that some rifamycin derivatives can specifically inhibit template-independent nucleotide chain elongation reactions.
authors.forename: S T
authors.initials: ST
authors.lastname: Jacob
authors.forename: K M
authors.initials: KM
authors.lastname: Rose
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D008930:Mitochondria, Liver / Q000201:enzymology; D015394:Molecular Structure; D009994:Osmolar Concentration; D011061:Poly A / Q000378:metabolism; D011062:Polynucleotide Adenylyltransferase / Q000037:antagonists & inhibitors*; D051381:Rats; D012294:Rifamycins / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D012294:Rifamycins; D011061:Poly A; D000255:Adenosine Triphosphate; D011062:Polynucleotide Adenylyltransferase