Lipolytic enzymes of the digestive organs of the crown-of-thorns starfish (Acanthaster planci): comparison of the stomach and pyloric caeca.

1. Stomach and pyloric caeca homogenates from the crown-of-thorns starfish hydrolysed p-nitrophenyl esters, alpha-naphthyl esters, cholesteryl oleate and tributyrin. The pyloric caeca contained the highest activities. 2. The p-nitrophenyl acetate hydrolytic activity eluted at 0.23 M NaCl on ion exchange chromatography while the p-nitrophenyl palmitate hydrolytic activity eluted between 0.2 and 1.0 M NaCl. 3. Polyacrylamide gel zymograms for alpha-naphthyl acetate hydrolytic activity revealed one major band and several minor bands of activity for both tissues. 4. Isoelectric focusing zymograms revealed one major band with a pI = 4.2 for both tissues, with an additional band at pI = 3.5 for pyloric caeca. 5. The pyloric caeca contained twice as much lipid as the stomach. Lipid extracts contained mixtures of steroids and steroid-esters; a cholesterol-like sterol was tentatively identified.