You can find nattokinase in the form of Japanese natto at a few restaurants and Japanese grocers.   The form in natto is vitamin k2 (mk-7).   

Another way to get k2 is to eat grass-fed beef and eggs from chickens raised on varied diets including seeds, grubs and grasses.  In fact a woman in France who died at the age of 116 (earlier this year?) attributed her longevity in part to eating two raw farm-fresh eggs daily.