Abstract
The inhibitory action of amylopectin sulfate (APS) on gastrointestinal proteases and experimental peptic ulcer was investigated with the following results : 1) APS inhibited pepsin, trypsin and chymotrypsin in vitro. Pepsin inhibition enhanced with the increasing concentration of APS and the maximum inhibition reached 100 %. On the other hand, the maximum inhibition of trypsin and chymotrypsin by APS was 60-70 %. 2) In a toluidine blue method at pH 3.0 and a 1 : 5 ratio of APS to protein, the affinity of APS for hemoglobin was strongest and the order of the affinity for other proteins was trypsin, chymotrypsin and pepsin. 3) In an experiment of cross electrophoresis of APS with protein, APS reacted with substrates and pepsin at pH 1.8 and reacted with enzymes alone at pH 7.8. 4) From the above results, the anti-pepsin action of APS may be due to a combination of APS and both substrate and pepsin, while anti-trypsin and anti-chymotrypsin actions of APS may be due to the combination of APS with enzymes. 5) APS strongly protected against ulceration and pepsin activity of gastric juice in pylorus ligated rats but did not prevent erosions in the glandular portion of the stomach induced by pyloric ligation and cold stress in spite of potent inhibition of pepsin activity.
