SOME OBSERVATIONS ON THE PANCREATIC AMYLASE AND INTESTINAL MALTASE OF THE CHICK

Abstract

The digestive enzymes amylase and maltase were studied in acetone-dried powders or homogenates of the pancreatic and small intestinal tissues and small intestinal contents obtained from chicks of various ages. The stability of pancreatic amylase, which was relatively low in 0.15 M sodium chloride, was increased markedly by the presence of 0.02 M barbiturate buffer. The pH optimum of pancreatic amylase (chloride-activated) was 7.0 whereas that of intestinal maltase was 6.9. High levels of pancreatic amylase activity were found in the newly-hatched chick but these levels decreased during the following 20 days and then remained constant. The contrast between the high amylase and low maltase activities in the contents of the small intestine suggested that molecules of maltose, formed by the hydrolysis of starch, were absorbed as such by the mucosal cells. It appeared that maltose could be absorbed with equal facility from all sections of the small intestine of the 10-day-old chick but in the older birds maltose absorption seemed to occur more readily from the upper small intestine than from the duodenum and lower small intestine. A modified method for the determination of maltase activity is described.