Serum endocuclease secreted into body fluids by a wide variety of exocrine and endocrine organs (PubMed:9395327). Expressed by non-hematopoietic tissues and preferentially cleaves protein-free DNA (By similarity). Among other functions, seems to be involved in cell death by apoptosis (By similarity). Binds specifically to G-actin and blocks actin polymerization. Preferentially attacks double-stranded DNA and produces oligonucleotides with 5'-phospho and 3'-hydroxy termini (PubMed:9395327). Endonucleolytic cleavage to 5'-phosphodinucleotide and 5'-phosphooligonucleotide end-products. Divalent metal cations. Prefers Ca(2+) or Mg(2+) which have a synergistic effect on activation. Optimum pH is 8.5. Monomer. Secretory protein, stored in zymogen granules and found in the nuclear envelope. Belongs to the DNase I family.