Laboratoire de Phylogénie moléculaire des Annélides, ER 87 CNRS, Groupe de Neuroendocrinologie des Hirudinées, SN3, Université des Sciences et Technologies de Lille, F-59655, Villeneuve d'Ascq Cedex, France
Abstract:
This article reports the purification of a renin-like enzyme (an aspartyl protease) from head parts of the leech Theromyzon tessulatum. After four steps of purification including gel permeation and anion exchange chromatographies followed by reversed-phase HPLC, this enzyme was purified to homogeneity. The renin-like enzyme (of 32 kDa) hydrolyses at neutral pH and at 37°C, the Leu10-Leu11 bond of synthetic porcine angiotensinogen tetradecapeptide yielding the angiotensin I and the Leu11-Val12-Tyr13-Ser14 peptide as products, with a specific activity of 1.35 pmol AI/min/mg (Km 22 μM; Kcat 2.7). The hydrolysis of angiotensinogen is inhibitable at 90% by pepstatin A (IC50 = 4.6 μM), consistent with a renin activity. This is the first biochemical evidence of renin-like enzyme in invertebrates.