▁above ▁ 1 0 − 9 − 1 0 − 1 0 ▁M . ▁T iter ▁of ▁la ct o fer rin ▁in ▁the ▁blood ▁corresponds ▁to ▁this ▁particular ▁" transition ▁concentration " ▁and ▁thus ▁la ct o fer rin ▁in ▁the ▁blood ▁should ▁be ▁presented ▁both ▁as ▁a ▁mon omer ▁and ▁t et ram er . ▁Many ▁functional ▁properties ▁of ▁la ct o fer rin ▁depend ▁on ▁its ▁o lig omer ic ▁state . ▁In ▁particular , ▁mon omer ic , ▁but ▁not ▁t et ram er ic ▁la ct o fer rin ▁can ▁strongly ▁bind ▁to ▁DNA . ▁ ▁Function ▁ ▁L act o fer rin ▁belongs ▁to ▁the ▁inn ate ▁imm une ▁system . ▁A part ▁from ▁its ▁main ▁bi ological ▁function , ▁namely ▁binding ▁and ▁transport ▁of ▁iron ▁ ions , ▁la ct o fer rin ▁also ▁has ▁ant ib acter ial , ▁ant iv iral , ▁ant ip ar as it ic , ▁catal yt ic , ▁anti - can cer , ▁and ▁anti - aller g ic ▁functions ▁and ▁properties . ▁ ▁En zym atic ▁activity ▁of ▁la ct o fer rin ▁L act o fer rin ▁hydro ly zes ▁R NA ▁and ▁exhib its ▁the ▁properties ▁of ▁p yr im id ine - specific ▁secret ory ▁rib on uc leases . ▁In ▁particular , ▁by ▁destroy ing ▁the ▁R NA ▁gen ome , ▁milk ▁R N ase ▁in hib its ▁reverse ▁trans cription ▁of ▁retro vir uses ▁that ▁cause ▁breast ▁cancer ▁in ▁m ice . ▁Par