Proteins Flashcards
Basic unit of proteins
Amino Acid
Amino acid structure
Amino group
Sude chain
Carboxyl group
Protein structure
Single amino acid + single amino acid = dipeptide
Protein digestion in stomach
HCl
Pepsin
Rennin/chymosin
Activates pepsinogen
HCl
Complex proteins - polypeptides
Pepsin
Enzyme only present during infancy and childhood
Act on the casein of milk to produce curd - allows slow passage through the small intestine
Rennin/chymosin
Types of secretions in the small intestine
Pacreatic secretions
Intestinal secretions
Pancreatic secretions
Trypsin
Chymotrypsin
Carboxypeptidase
Breaks long protein chains into small polypeptides and dipeptides
Trypsin
Continues protein-splitting action of trypsin
Chymotrypsin
Attacks carboxyl ends or peptide chains - small peptides and free amino acids
Carboxypeptidase
Intestinal Secretions
Aminopeptidase
Dipeptidase
Attacks amino end of peptude chains - small peptides and free amino acids
Aminopeptidase
Final enzyme in the protein-splitting action system
Completes the job by breaking the remaining dipeptides into two individual amino acids
Dipeptidase
No absorption of peptides longer than 3 amino acids
Di- and tri-peptides more rapidly absorbed than individual amino acids
Small intestine digestion
Most amino acid go to the
Liver
Unlike carbohydrates and fat, proteins are
Continuously recycled
Proteins metabolism
Protein synthesis
Protein breakdown
Exported out to the systemic circulation
Protein synthesis (anabolism)
20g
Protein breakdown (catabolism)
60g
Exported out of the sytemic circulation
20g
Proteins provide
Amino acids
Nitrogen atoms
Energy
Almost and exclusive source of nitrogen to the body
Dietary protein