sentences:  Apo(a), a distinct feature of the Lp(a) particle, binds to immobilized fibronectin and endows Lp(a) with the serine-proteinase-type proteolytic activity.Nonetheless, individuals without Lp(a) or with very low Lp(a) levels seem to be healthy.Thus, plasma Lp(a) is not vital, at least under normal environmental conditions.