Inhibition of DNA polymerase of avian myeloblastosis virus by an alkaloid extract from Narcissus tazetta L

An alkaloid extract of the Sacred Lily (narcissus tarzetta L.), a medicinal plant, inhibits the purified DNA polymerase from Avian myeloblastosis virus. The mechanism of action of this inhibitor, differs from that of other known inhibitors. The inhibitor physically combines with the polymerase, it does not affect the binding of the template to the enzyme as demonstrated by classical non-competitive inhibition kinetics and affects either the initiation or elongation phase of the polymerization reaction. The inhibition is the same whether viral 70S RNA or poly d(AT) is used as template.