The antiproteolytic enzyme ofAscaris lumbricoidesvar.suis

Abstract

1. The inhibitory effect ofAscarisextract on pepsin and trypsin is confirmed. This inhibition is shown not to occur with papain.2. The inhibitory effect is shown to be brought about by a combination of the anti-enzyme with the enzyme and not by any of the other possible causes.3. The extract is shown to have a proteolytic as well as an inhibitory action and these two properties are shown to be due to one and the same substance.4. The term “ascarase” is suggested for this substance.5. The ascarase is shown to be a readily diffusible substance of the order of a primary albumose, is precipitated by ammonium sulphate and 70% alcohol, is only slowly destroyed in acid but rapidly in alkali and is not digested by trypsin. It combines with the greatest quantities of substrate atpH 5–7.6. Ascarase is found in the various tissues of the worm in the following order: ovary, oesophagus, gut, body fluid, ovojector, lateral line, uterus and cuticle. A similar order was found for the male.7. The results found by de Wael (1933) forT. saginatado not apply to Ascaris.8. The effect of the ascarase on the host and its function in the worm are discussed.