pancreatic enzyme
Meaning of pancreatic enzyme: The digestive proteins the pancreas pours into the gut, each cutting apart a different component of a meal.
Definition of pancreatic enzyme
A pancreatic enzyme is one of the digestive proteins the pancreas makes and releases into the small intestine. Between them they break starch, fat and protein into fragments small enough to be absorbed. Most leave the gland in an inactive form and are switched on only once they reach the gut, an arrangement that keeps them from digesting the pancreas itself.
Which enzymes are there?
| Enzyme | Acts on | Producing |
|---|---|---|
| Amylase | Starch | Simple sugars |
| Lipase, with a helper called colipase | Fat | Fatty acids and glycerol |
| Trypsin and chymotrypsin | Protein | Short chains and amino acids |
| Nucleases | DNA and RNA from food | Individual building blocks |
Why does the pancreas not digest itself?
Three safeguards work together. The protein-cutting enzymes are packaged as inactive precursors. A separate protein inside the gland stands ready to block any that switch on early. Activation depends on an enzyme found only in the lining of the duodenum, which flips the first one on and lets it activate the rest. When that system fails and activation happens inside the gland, the result is pancreatitis, the pancreas digesting its own tissue. The pancreatic juice that carries the enzymes is also rich in bicarbonate, which neutralizes stomach acid so the enzymes can work at all.
What happens when there are too few?
Chronic inflammation, cystic fibrosis, a tumor blocking the duct or removal of part of the gland can all leave too little enzyme reaching the gut. Fat is affected first, because no other organ makes much lipase. Stools become pale, greasy, bulky and hard to flush, weight falls despite a normal appetite, and the vitamins that need fat to be absorbed run short. Replacement capsules holding a mixture of the same enzymes are taken with food, coated so that stomach acid does not destroy each enzyme before it arrives.
Do other organs make digestive enzymes too?
Digestion is a relay rather than one event. Saliva begins work on starch, and the stomach adds an acid-loving protein cutter along with a small amount of fat splitting activity. The pancreas then does the bulk of the work in the first stretch of small intestine. Finally the lining of the intestine contributes enzymes anchored to its own surface, which split the last sugar and peptide fragments immediately before they are absorbed. Bile from the liver is not an enzyme at all: it breaks fat into fine droplets so that lipase has far more surface to work on.
Also known as
Used in a sentence
Pancreatic enzyme replacement was started because of persistent greasy stools and weight loss.
Good to know
Amylase and lipase levels in blood rise when the pancreas is inflamed, which reflects enzyme leaking into the bloodstream rather than anything about digestion, so they do not measure whether enough enzyme is reaching the gut.
Word origin
Where “pancreatic enzyme” comes from
Pancreas comes from the Greek pan, meaning all, and kreas, meaning flesh. Enzyme comes from the Greek en, in, and zyme, leaven.