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Digestion of Protein

GASTROINTESTINAL PHYSIOLOGY

•Pepsinogen

Peptides

Jjpócarboxypcptidase

gpymotrypstmigen

SpTrypsinogen

■-■lir. .• ’ i■ i

cholecystokinin

Partcreas

Peptidases

Peptfdeś-

^PWase

Aminopołyp*ptid.; Dipeptidase ( artx>xypepdt&*e Endopeptićłaso

tripeptides

Lymphatics-

(to lhoradc duet and thencc to venous system)

Portal vein (to liverl

\ Amino ij^acids

Epitheiial cells

Figurę 7.35 Digestion of Protein_

Protein digestion begins in the stornach through the action of HCI and pepsin. Pancreatic proteases and peplidases associated with the glycocalyx of the intestinal epitheiial cells continue this process, yielding amino adds, tripeptides, and dipeplides, which are then absorbed by the intestinal epitheiial cells. The panereas also secretes proelastase (not shown in figurę). The tripeptides and dipeptides are absorbed coupled to II\ while the amino acids are absorbed cou-pled to Na' (see Figurę 734).

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