Secretion of an aminopeptidase during transition of third- to fourth-stage larvae of Ascaris suum

• Published in: The Journal of parasitology Vol. 83; no. 5; pp. 780 - 784
• Main Authors: Rhoads, L, Fetterer, R.H, Urban, J.F. Jr
• Format: Journal Article
• Language: English
• Published: Lawrence, KS American Society of Parasitologists 01-10-1997
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Aminopeptidases - antagonists & inhibitors; Aminopeptidases - metabolism; Aminopeptidases - secretion; Animals; Anti-Bacterial Agents - pharmacology; ASCARIS SUUM; Ascaris suum - enzymology; Ascaris suum - growth & development; Biochemistry; Biochemistry-Physiology; Biological and medical sciences; ENZYME INHIBITORS; Enzymes; ENZYMIC ACTIVITY; Fundamental and applied biological sciences. Psychology; HIDROLISIS; Hydrogen-Ion Concentration; HYDROLYSE; HYDROLYSIS; INHIBICION; INHIBIDORES DE ENZIMAS; INHIBITEUR D'ENZYME; INHIBITION; Insect larvae; Invertebrates; ISOELECTRIC POINT; Larva - enzymology; Larva - growth & development; LARVAE; Larval development; LARVAS; LARVE; Leucine - analogs & derivatives; Leucine - pharmacology; Life cycle. Embryology. Development; MOLECULAR WEIGHT; Molting; MOULTING; MUDA; MUE; Nemathelminthia. Plathelmintha; NEMATODA; Nematode larvae; Parasitology; PEPTIDASAS; PEPTIDASE; PEPTIDASES; Peptides; PESO MOLECULAR; Phenanthrolines - pharmacology; Physiology. Development; POIDS MOLECULAIRE; POINT ISOELECTRIQUE; Protease Inhibitors - pharmacology; Proteins; PUNTO ISOELECTRICO; SECRECION; SECRETION; Substrate Specificity; Swine; Enzyme; Secretion; Aminopeptidases; Parasite; Molt; Peptidases; Enzymatic activity; Larva; Helmintha; Ascaris suum; Development; Hydrolases; Nemathelminthia; Invertebrata; Nematoda
• ISSN: 0022-3395; 1937-2345
• DOI: 10.2307/3284267

Protease activity was identified in culture fluids collected during in vitro development of L3 to L4 larval stages of Ascaris suum. Fluorogenic peptide substrates with unblocked N-termini were specifically hydrolyzed indicating aminopeptidase activity; a terminal arginyl residue was preferred. Culture fluids did not hydrolyze fluorogenic peptide substrates with blocked N-termini (endopeptidase substrates). The aminopeptidase activity was inhibited by 1,10-phenanthroline (metalloprotease inhibitor) and by amastatin and bestatin (aminopeptidase inhibitors); AEBSF (serine protease inhibitor), Z-phe-ala-FMK and E-64 (cysteine protease inhibitors), and pepstatin A (aspartyl protease inhibitor) had little effect on activity. The apparent molecular weight of the aminopeptidase was estimated by sucrose density gradient centrifugation at 293 kDa. The aminopeptidase displayed an acidic isoelectric point of 4.7. The peak secretion of the aminopeptidase was temporally associated with molting and suggests a function for the protease in this complex process.