ISOLATION OF A RENIN-LIKE ENZYME FROM THE LEECH THEROMYZON TESSULATUM

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 degrees C, the Leu(10)-Leu(11) bond of synthetic porcine angiotensinogen tetradecapeptide yielding the angiotensin I and the Leu(11)-Val(12)-Tyr(13)-Ser(14) peptide as products, with a specific activity of 1.35 pmol AI/min/mg (K-m 22 mu M; K-cat 2.7). The hydrolysis of angiotensinogen is inhibitable at 90% by pepstatin A (IC50 = 4.6 mu M), consistent with a renin activity. This is the first biochemical evidence of renin-like enzyme in invertebrates.