TY - JOUR
T1 - Leucine aminopeptidase of the human blood flukes, Schistosoma mansoni and Schistosoma japonicum
AU - McCarthy, E.
AU - Stack, C.
AU - Donnelly, S.M.
AU - Doyle, S.
AU - Mann, V.H.
AU - Brindley, P.J.
AU - Stewart, M.
AU - Day, T.A.
AU - Maule, Aaron
AU - Dalton, J.P.
PY - 2004/5
Y1 - 2004/5
N2 - An array of schistosome endoproteases involved in the digestion of host hemoglobin to absorbable peptides has been described, but the exoprotease responsible for catabolising these peptides to amino acids has yet to be identified. By searching the public databases we found that Schistosoma mansoni and Schistosoma japonicum express a gene encoding a member of the M17 family of leucine aminopeptidases (LAPs). A functional recombinant S. mansoni LAP produced in insect cells shared biochemical properties, including pH optimum for activity, substrate specificity and reliance on metal cations for activity, with the major aminopeptidase activity in soluble extracts of adult worms. The pH range in which the enzyme functions and the lack of a signal peptide indicate that the enzyme functions intracellularly. Immunolocalisation studies showed that the S. mansoni LAP is synthesised in the gastrodermal cells surrounding the gut lumen. Accordingly, we propose that peptides generated in the lumen of the schistosome gut are absorbed into the gastrodermal cells and are cleaved by LAP to free amino acids before being distributed to the internal tissues of the parasite. Since LAP was also localised to the surface tegument it may play an additional role in surface membrane re-modelling. (C) 2004 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.
AB - An array of schistosome endoproteases involved in the digestion of host hemoglobin to absorbable peptides has been described, but the exoprotease responsible for catabolising these peptides to amino acids has yet to be identified. By searching the public databases we found that Schistosoma mansoni and Schistosoma japonicum express a gene encoding a member of the M17 family of leucine aminopeptidases (LAPs). A functional recombinant S. mansoni LAP produced in insect cells shared biochemical properties, including pH optimum for activity, substrate specificity and reliance on metal cations for activity, with the major aminopeptidase activity in soluble extracts of adult worms. The pH range in which the enzyme functions and the lack of a signal peptide indicate that the enzyme functions intracellularly. Immunolocalisation studies showed that the S. mansoni LAP is synthesised in the gastrodermal cells surrounding the gut lumen. Accordingly, we propose that peptides generated in the lumen of the schistosome gut are absorbed into the gastrodermal cells and are cleaved by LAP to free amino acids before being distributed to the internal tissues of the parasite. Since LAP was also localised to the surface tegument it may play an additional role in surface membrane re-modelling. (C) 2004 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.
UR - http://www.scopus.com/inward/record.url?scp=11144355066&partnerID=8YFLogxK
U2 - 10.1016/j.ijpara.2004.01.008
DO - 10.1016/j.ijpara.2004.01.008
M3 - Article
SN - 0020-7519
VL - 34(6)
SP - 703
EP - 714
JO - International Journal for Parasitology
JF - International Journal for Parasitology
IS - 6
ER -
