Which of the following statements is true about protein digestion?: (A) Protein digestion stas with the salivary action, (B) Trypsinogen is conveed to trypsin by the action of bicarbonate in duodenum, (C) Trypsin and chymotrypsin are exopeptidases, (D) 10%-20% protein digestion occurs by pepsin action in stomach.
Answer is D. - Saliva does not contain proteolytic enzyme; protein digestion begins in the stomach by the action of pepsin. - Trypsinogen is conveed to trypsin by the action of enterokinase in duodenum. - Trypsin and chymotrypsin are endopeptidases; carboxypeptidase and aminopeptidase are exopeptidases. - Of the total protein digestion, 10%-20% occurs by the action of pepsin.