Secretion of Gastric
Enzymes
by Hari Mani
Gastric Enzymes
Enzymes that are secreted by the stomach are called
gastric enzymes.
These include:
Pepsin
Gelatinase
Gastric amylase
Gastric lipase
Pepsin
Main enzyme secreted by stomach
Secreted by the chief cells as pepsinogen
Pepsin degrades proteins into peptides
Pepsinogen is activated by hydrochloric acid
(secreted by parietal cells) to form pepsin
Gelatinase
Proteolytic enzyme that allows a living organism to
hydrolyze gelatin into its sub-compounds
These sub-compounds (polypeptides, peptides and
amino acids) can then cross over the cell membrane
and be utilized by the cell.
Gastric Amylase
Enzyme that breaks down starch into sugars
This process occurs mainly in the mouth but the
stomach does secrete minor amounts of amylase to
continue starch degradation into di- and
trisaccharides
Gastric Lipase
An acidic lipase that aids in the transport and
processing of triglyercides, oils and fats
Secreted by chief cells in the mucosa of the gastric
fundus (a portion of the left side of the stomach)
Does not require bile acid or colipase (unlike alkaline
lipases, i.e. pancreatic lipase) for optimal enzymatic
activity
In infants, makes up to 50% of lipase activity