Pepsin is an enzyme found in the human stomach that breaks down protein and will not break down starch because enzymes only work for specific substrates.
<h3>What is an Enzyme?</h3>
This is defined as a biological catalyst which helps to speed the rate of chemical reaction in the body. They are also substrate specific which means they can't act on any type of substance.
Pepsin is an enzyme which breaks down protein substances which is therefore the reason why it won't act on other food substances such as carbohydrate etc.