Mechanism of action of rifampin on Mycobacterium smegmatis.

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White RJ, Lancini GC, Silvestri LG

Mechanism of action of rifampin on Mycobacterium smegmatis.

J Bacteriol. 1971 Nov;108(2):737-41.

PubMed ID

4942761 [ View in PubMed

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Abstract

Deoxyribonucleic acid (DNA)-dependent ribonucleic acid (RNA) polymerase (EC 2.7.7.6) isolated from a rifampin-sensitive strain of Mycobacterium smegmatis was 90% inhibited by 1 mug of rifampin per ml; enzyme from a rifampin-resistant mutant was not affected by this concentration of antibiotic. Inhibition of phenylalanine-1-(14)C incorporation by rifampin in growing cultures was complete about 6 min after addition of antibiotic. Under the same conditions, uracil-2-(14)c incorporated was blocked after 1.5 to 2 min. Rifampin kills M. smegmatis very slowly. When rifampin-inhibited cultures were transferred to a rifampin-free medium, there was a partial resumption of uracil-2-(14)C incorporation, even in the presence of chloramphenicol. We conclude that a primary event in the inhibition of M. smegmatis by rifampin is the block of DNA-dependent RNA polymerase.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Rifampicin	DNA-directed RNA polymerase subunit beta	Protein	Escherichia coli (strain K12)	Yes	Inhibitor	Details