Isolation and Inhibitory Activity of Angiotensin 1-Converting Enzyme Inhibitor in Enzymatic Hydrolyzates of Water-and Hot-Water-Extracts from Sea Anemone, Actinia equinia.

Abstract

Author describe a method of extraction and partial purification of phosphoproteins from Sea anemone, actinia equinia. The extraction of the phosphoproteins was carried out with water and hot water. The sea anemone contained two kinds of phosphoproteins (W-P-1, W-P-2) in the water extracts and two kinds of phosphoproteins (H-P-1, H-P-2) in the hot water extracts by gel filtration chromatography on Sephadex G-50, respectively. In addition, the ACE inhibitor phosphopeptides of H-P-2 and W-P-2 were further purified by ultrafiltration and by Sephadex G-15 chromatography. Inhibitors which inhibit the angiotensin 1-converting enzyme (ACE) were prepared from the trypsin and pepsin digests of the water-extracts and hot-water-extracts of sea anemone. The inhibitory activity of ACE in the trypsin digests of the hot water extracts (H-P-2) was fractionated into three major phosphopeptides fractions of H-P-2-1, H-P-2-2 and H-P-2-3 by gel filtration chromatography on sephadex G-15. The inhibitory activity of ACE in the pepsin digests of the water extracts (W-P-2) was fractionated into three major phosphopeptide fraction of W-P-2-1, W-P-2-2 and W-P-2-3 by gel filtration chromatography on sephadex G-15. The IC_<50> values of H-P-1, H-P-2, W-P-1 and W-P-2 of phosphopeptides for ACE were 23.2, 15.9, 219.3 and 56.9 mg protein /ml, respectively. The inhibition of ACE of the six kinds of phosphopeptides fractions (H-P-2-1, H-P-2-2, H-P-2-3, W-P-2-1, W-P-2-2, and W-P-2-3) was analyzed in vitro. The IC_<50> values of H-P-2-1, H-P-2-2, H-P-2-3, W-P-2-1, W-P-2-2 and W-P-2-3 of phosphopeptides for ACE were 1.63, 1.41, 0.43, 4.10, 1.93 and 1.61 mg protein /ml, respectively. The H-P-2-3 fraction had most inhibition activity and showed 0.43 mg protein /ml inhibition against ACE at IC50 value. The amino acid compositions of the phosphopeptides (H-P-2-1, H-P-2-2, H-P-2-3, W-P-2-1, W-P-2-2 and W-P-2-3) were characterized by relatively high percentage for Glu, Asp, Gly, Ala, Val, Leu, Tyr and Lys. It has been demonstrated that the H-P-2-1, H-P-2-2, H-P-2-3, W-P-2-1, W-P-2-2 and W-P-2-3 contained about 2.9%, 7.8%, 37.9%, 28.8%, 43.5% and 71.5% as phosphonate-phosphorus of total phosphorus. The results above, the Sephadex G-15 gel filtration patterns of the active fractions obtained from the Sephadex G-50 column chromatography indicated that the molecular weight of the phosphopeptide was about 200～3000.