Details

Autor(en) / Beteiligte

• Rhodes, Marvin B.
• Marsh, Connell L.
• Ferguson, Donald L.

Titel

Ascaris suum: Purification and characterization of an intestinal aminopeptidase

Ist Teil von

• Experimental parasitology, 1969-01, Vol.26 (2), p.150-155

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

1969

Quelle

Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)

Beschreibungen/Notizen

• Semipurified preparations of an aminopeptidase from intestinal extracts of Ascaris suum had low specific activity (.03 units per milligram of protein), a large molecular size, and a limited solubility. Treatment of these preparations with a mixture of chymotrypsin and trypsin resulted in the release of ninhydrin-staining components during the incubation period (6 hours at 37 °C) but the aminopeptidase retained over 90% of its enzymatic activity. The enzyme was now soluble at pH 5 and migrated as a single band by starch-gel electrophoresis after it had been further purified by sucrose-density gradient centrifugation. The purified aminopeptidase was maximally activated by Co 2+ compared to other divalent metallic ions. The enzyme had a pH optimum of 6.8, a specific activity of 2.7 units per milligram of protein, and a calculated Michaelis constant of 2.0 × 10 −4 M. Progressive autolysis of crude intestinal homogenates also resulted in increasing amounts of a component which appeared similar to that of the purified aminopeptidase.