Polyamine-stimulated binding of diamine oxidase to DNA.

Diamine oxidase is a Cu-containing enzyme which intracellularly participates in the regulation of the levels of putrescine, spermidine and spermine and in this process produces growth inhibitory amino aldehydes and hydrogen peroxide. Extracellularly, the enzyme participates in the inactivation of biogenic amines, notably histamine. Here we present evidence that in the presence of polyamines, diamine oxidase has the ability to bind DNA and to oxidise DNA-bound polyamines. The enzyme associates with chromosomal DNA since it can be released from human placental DNA by treatment with DNase I and it may be involved in the degradation of DNA. Thus, diamine oxidase may belong to a new class of DNA-binding proteins.