Protein enzymes: protease, bromelain and papain

Protein is part of most meals: the chicken in a rice dish, the eggs at the start of the day, the chickpeas in hummus, the lentils in a soup. Before your body can use it, that protein has to be broken down, and the enzymes that do this work are called proteases.

This article explains what protein is made of, how your body breaks it down, and the three protein enzymes in Goodness Digestive Enzymes: protease, bromelain from pineapple and papain from papaya.

What is protein made of?

The US National Library of Medicine (MedlinePlus) describes protein as a chain of amino acids. Every cell in the human body contains protein, and you need protein in your diet to repair cells and make new ones.

During digestion, the protein in food is broken down into its amino acids. Some of these, the essential amino acids, cannot be made by the body and must come from food. MedlinePlus notes that they do not all have to be eaten at once: the balance over the whole day is what matters.

How does your body break down protein?

According to NIDDK, part of the US National Institutes of Health (NIH), protein digestion happens in stages:

1. Stomach. Glands in the stomach lining make stomach acid and enzymes, and the stomach muscles mix them with food. Protein is the main food the stomach starts to break down.
2. Pancreas. The pancreas makes a digestive juice with enzymes that break down proteins, as well as carbohydrates and fats, and delivers it to the small intestine.
3. Small intestine. The small intestine adds its own digestive juice, which mixes with the juice from the pancreas to complete the breakdown of proteins.

The end result is amino acids. A useful picture is a long chain of beads: digestion cuts the chain into shorter pieces, and then into single beads.

What is a protease?

"Protease" is a general name rather than a single enzyme. A 2021 review of bromelain in the journal Life describes protein-digesting enzymes as "proteolytic enzymes or proteases", and a 2025 review of food enzymes in Food Science & Nutrition uses the names peptidases and proteases for the same group.

Your stomach and pancreas make proteases of their own. Proteases are also made by microorganisms and found in plants, and both sources are used to produce enzymes for food, according to the 2025 review.

In Goodness Digestive Enzymes, protease works alongside two plant enzymes, bromelain and papain. All 13 enzymes come from microbial and plant sources.

What is bromelain, and where does it come from?

The US National Center for Complementary and Integrative Health (NCCIH) describes bromelain as a group of enzymes that break down proteins, found in the stem and fruit of the pineapple plant.

The 2021 review in Life adds detail. There are two main forms: stem bromelain, from the inedible stem, and fruit bromelain, from the fruit itself. Much of the plant's bromelain is in the stem, and commercial bromelain is usually made from pineapple stems.

Bromelain's effect on protein is well known in the food industry. The 2025 review notes that bromelain breaks down the proteins in meat fibres, which is why it is used to tenderise meat, and that it is also used in baking and cheese making.

What is papain, and where does it come from?

Papain comes from the papaya plant. A 2023 study in the journal Foods lists papain, together with a related enzyme called chymopapain, among the enzymes found in papaya fruit and in papaya latex, the milky sap of the plant.

According to the 2025 review, papain is widely studied and widely used in food processing. It can break down practically any protein found in meat, including the tougher connective parts, which is why it is used as a meat tenderiser. It is also used in baking.

Are bromelain and papain related?

Yes. The 2023 study in Foods places bromelain and papain in the same family of plant proteases, along with actinidin from kiwi fruit and ficin from figs. All of them work on protein.

The same study notes that enzymes in this family have been reported to cause reactions in some people. If you are sensitive to pineapple, papaya, kiwi or figs, read Digestive enzymes, medicines and allergies and ask your doctor or pharmacist before using a supplement that contains bromelain or papain.

Which foods contain the protein these enzymes work on?

MedlinePlus lists protein sources from both animals and plants:

Many everyday dishes bring several of these together: rice with chicken and yoghurt, a plate of hummus and falafel, eggs with cheese and bread.

How do the three protein enzymes work together?

In Goodness Digestive Enzymes, protease, bromelain and papain help break down protein from meat, fish, eggs, dairy and legumes. They form one of four groups; the other nine enzymes work on starch and sugars, fats, and plant fibre:

• Carbohydrate enzymes: amylase, lactase and more
• Lipase and fat digestion
• Fibre enzymes

For a wider view of how digestion works, start with What do digestive enzymes do?. The Ingredients page lists all 13 enzymes, and the How to use page gives the directions and safety notes.

Goodness Digestive Enzymes is a food supplement that supports healthy digestion. It does not replace a varied, balanced diet.