EFFECT OF LIPID ON PROTOHEME FERRO-LYASE

1. 1. Protoheme ferroy-lyase (EC 4.99.1.1), extracted from chicken erythrocyte stroma with sodium cholate, showed similar properties to those of duck erythrocyte stroma which were reported previously. 2. 2. The preparation extracted with cholate showed high enzyme activity and contained lipids, while that extracted with 0.4 M KCl contained little lipid and showed little enzyme activity. Crude lipids from acetone-dried powder of chicken erythrocyte stimulated heme synthesis when they were added to the 0.4 M KCl-extracted preparation. Crude lipids from acetone-treated egg yolk cake also stimulated heme synthesis. When the lipids were previously digested with Naja naja phospholipase A (EC 3.1.1.4), the stimulating effect was increased in the presence of cholate and decreased in the absence of cholate. 3. 3. The effects of purified lipids on 0.4 M KCl-extracted preparation were as follows. Acidic phospholipids, phosphatidylethanolamine and lysophospholipids were effective, while choline-containing lipids were ineffective. Palmitate was effective, whereas tripalmitin was ineffective. In the presence of cholate, choline-containing lipids were effective, acidic lipids and phosphatidylethanolamine were slightly effective or neutral, and lyso-lipids were neutral. The effects of crude lipids could be explained by those of pure phospholipids. Sonication of lipid gave stronger stimulation than manual shaking. 4. 4. Detergency and charge of phospholipids were discussed in relation to the mechanism of protoheme ferro-lyase. © 1969.