Digestion of haemoglobin by schistosomes: 35 years on.

Adult schistosomes obtain nutrients by digesting haemoglobin, which they obtain from ingested host red blood cells. Here John Dalton, Angela Smith, Karen Clough and Paul Brindley argue that a cathepsin L proteinase recently identified in their laboratory as the predominant cysteine proteinase activity of Schistosoma mansoni may play the leading role in haemoglobin digestion. They discuss the importance of elucidating the roles of both cathepsin B and cathepsin L in the digestion of haemoglobin, since both should be considered important targets to which novel schistosomicidal agents could be directed.