{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Protein Digestion 111309 - PROTEINS PEPTIDES We consume...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1 P ROTEIN D IGESTION & A BSORPTION ( PG . 189-194) Lia M. Nightingale, Ph.D. P ROTEINS & P EPTIDES We consume ~100 grams of exogenous protein per day from: Animal products (meat, dairy, etc.) Plant proteins (legumes, nuts, etc.) We get ~200 grams of endogenous protein from: Digestive enzymes Sloughed cells Digested by efficient proteases Lys Lys Lys Gly Gly Val His Met Phe Only ~10 grams lost/day in feces. P ROTEIN D IGESTION - M OUTH No protein digestion occurs in the mouth P ROTEIN D IGESTION - S TOMACH HCl is released from parietal cells in response to gastrin 1. Denatures 2 , 3 , & 4 structure of protein 2. Converts pepsinogen (inactive) to pepsin (active) HCl or Pepsin Removes 46 amino acids to activate Pepsinogen Pepsin P ROTEIN D IGESTION - S TOMACH Pepsin is an endopeptidase Lys Tyr Lys Trp Val Met His Trp Phe Results in large polypeptides, oligopeptides, & free amino acids. Digests internal peptide bonds P ROTEIN D IGESTION - SI Chyme release into SI stimulates release of secretin & CCK (cholecystokinin) Secretin & CCK stimulate release of bicarbonate , water, electrolytes, & zymogens from pancreas Neutralizes stomach acid Inactive enzymes
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon