TY - JOUR
T1 - Starch and glucose oligosaccharides protect salivary-type amylase activity at acid pH
AU - Rosenblum, J. L.
AU - Irwin, C. L.
AU - Alpers, D. H.
PY - 1988/1/1
Y1 - 1988/1/1
N2 - Salivary-type amylase may significantly contribute to duodenal starch hydrolysis in exocrine pancreatic insufficiency, provided that gastric inactivation does not occur. We investigated the effect of starch and its hydrolytic products, therefore, on salivary amylase activity in vitro at low pH. When incubated at pH 3 in the presence of 1% starch, 56% of the initial activity of amylase purified from saliva remained after 60 min at 37°C compared with only 6% without starch. Similar protection of amylolytic activity was observed using human milk, which also contains a salivary-type amylase. In addition, partially hydrolyzed starch protected salivary amylase activity at pH 3, and purified glucose oligomers ranging in length from two to seven glucose molecules protected amylase in a concentration-dependent manner. Lactose, sucrose, and glucose, however, were ineffective in sparing amylase. Starch protected amylase activity even in the presence of pepsin, and maltotriose conferred striking protection below pH 3. These studies indicate that salivary-type isoamylases are protected in a simulated gastric environment by substrates of amylase as well as its end products of hydrolysis.
AB - Salivary-type amylase may significantly contribute to duodenal starch hydrolysis in exocrine pancreatic insufficiency, provided that gastric inactivation does not occur. We investigated the effect of starch and its hydrolytic products, therefore, on salivary amylase activity in vitro at low pH. When incubated at pH 3 in the presence of 1% starch, 56% of the initial activity of amylase purified from saliva remained after 60 min at 37°C compared with only 6% without starch. Similar protection of amylolytic activity was observed using human milk, which also contains a salivary-type amylase. In addition, partially hydrolyzed starch protected salivary amylase activity at pH 3, and purified glucose oligomers ranging in length from two to seven glucose molecules protected amylase in a concentration-dependent manner. Lactose, sucrose, and glucose, however, were ineffective in sparing amylase. Starch protected amylase activity even in the presence of pepsin, and maltotriose conferred striking protection below pH 3. These studies indicate that salivary-type isoamylases are protected in a simulated gastric environment by substrates of amylase as well as its end products of hydrolysis.
UR - https://www.scopus.com/pages/publications/0023908151
M3 - Article
C2 - 2452576
AN - SCOPUS:0023908151
SN - 0002-9513
VL - 254
SP - 17/5
JO - American Journal of Physiology - Gastrointestinal and Liver Physiology
JF - American Journal of Physiology - Gastrointestinal and Liver Physiology
IS - 5
ER -