Investigations into the digestion of protein substrates from mammalian hosts susceptible to Fasciola infection have shown that NEJ proteinases catalyse the hydrolysis of gelatin [54,55], collagen [43,44,56], fibronectin [57], serum albumin [12], immunoglobulins [58] and haemoglobin [28]. This evidence concerns the gene ALB and fascioliasis.