Question

How does intestinal juice contribute to the digestion of proteins? What provides the alkaline pH in the small intestine?

Answer 1

Hint: Intestinal juice includes collected works of enzymes. The proteases hydrolyze peptides into dipeptides and ultimately it gets hydrolyzed into amino acids. Pancreatic lipase splits down fats into diglycerides and monoglycerides. The nucleases of intestinal juice split down nucleic acids into nucleotides and nucleosides.

Complete answer: The enzymes that "work" in the small intestine requires an alkaline pH so as to have worked over the most favorable operating conditions.
The enzymes of the secretion (succus entericus) work on the top products received after the action of digestive juice on the proteins and pancreatic amylase converts polysaccharides into disaccharides. Disaccharidases like maltase, lactase, sucrase, etc., eventually digest the disaccharides.
Dipeptides, since produced, are acted upon by the peptidases present within the succus entericus which changes it into the uncomplicated absorbable amino acids. Mucus exuded by the goblet cells together with the bicarbonates from the pancreas forms an alkaline medium (7.8) within the intestine for the enzymatic actions and to guard intestinal mucosa from the acid.

Note:
Strong acids can end up injuring the lining of your intestine. The stomach is predominantly adapted to deal with these conditions but the small intestine is not adapted. Therefore, it needs the pH to be reduced to keep away from damage. In the end, the pH in the small intestine is altered through the use of bile - an alkaline substance created by the liver. Bile is essential as when food comes from the stomach, the hydrochloric acid used in the primary stages of digestion makes it excessively acidic.