Submitted to: Experimental Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 6, 1998
Publication Date: N/A
Interpretive Summary: The swine round worm, Ascaris suum, is responsible for significant economic losses by reducing production efficiency and causing organ condemnations at slaughter. Development of novel controls can be enhanced by a knowledge of the basic biology of this nematode. The results demonstrate that an aminopeptidase was present at high levels in the secretions of both adult and larval stages of A. suum and present in all tissues of the adult stage The enzyme may play a digestive function in providing essential amino acids or may function in the processing of essential molecules into their active forms. Inhibition of this enzyme might prevent parasite survival.
Technical Abstract: A metalloaminopeptidase was identified in culture fluids collected during in vitro cultivation of adult Ascaris suum. The enzyme was purified by anion-exchange and size- exclusion HPLC. The molecular weight of the enzyme was estimated at 293 kDa and consisted of subunits with apparent molecular weights of 153 and 142 kDa. The isoelectric point of the aminopeptidase was 4.7. The aminopeptidase displayed a substrate preferenc for terminal arginyl residues. Aminopeptidase activity also was present in muscle, female reproductive tissue, pharynx, pseudocoelomic fluid and intestine. Among the various tissues, aminopeptidase activity was highest in the intestines (3-8 times higher); the highest activity was found in culture fluids (3-fold higher than intestinal tissue). The aminopeptidase released by adult A. suum was enzymatically and biochemically identical to an aminopeptidase released during in vitro development of A. suum L3 to L4 larval stages.