Enzymes are proteins, produced by different cells of humans, animals, plants and microorganisms, which accelerate the rate of chemical reactions in living organisms. Like all catalysts, enzymes work by lowering the amount of activation energy needed for a reaction to occur and thus dramatically accelerating the rate of the reaction.

Without enzymes, these processes would not happen under normal physiological conditions and life as we know would not be possible.

Due to the need of different enzymes for different biochemical reactions, living organisms contain thousands of different enzymes. It is estimated that the human body contains more than 10.000 different enzymes, each of them with special function. Approximately only 10% of these are discovered yet.

When enzymes were first discovered scientists named them. Although they added the “in” suffix to most (such as Papain, Trypsin, Bromelain, Pepsin and Chymotrypsin) there was no uniformly accepted method of naming enzymes. 1956 the International Commission on Enzymes was established to develop a nomenclature system. Today enzyme’s name is derived from its substrate or the chemical reaction it catalyzes, with the word ending in “-ase”.

Now, each protein is given an Enzyme Classification Number (EC). The method of classification is by the type of reaction the enzyme catalyzes.

• EC 1 – Oxidoreductases
• EC 2 – Transferases
• EC 3 – Hydrolases
• EC 4 – Lyases
• EC 5 – Isomerases
• EC 6 – Ligases

Hydrolases (all therapeutic used Enzymes are Hydrolases) can be classified in their function groups:

• Proteases: also called proteinases, peptidases or proteolytic enzymes, function to split proteins.
• Lipases: function to digest or split lipids or fatty acids
• Amylases: function to breakdown carbohydrates

Enzymes were produced by living cells only and are necessary for all processes occur in our body, in the intestine, in blood, in the cells, and between the cells.

The different enzymes work in and between the cells in the body and in addition, intestinal cells produce alimentary enzymes, which split the food into such small molecules so they can be absorbed into the blood.

Most of the enzymes we need are produced from cells of our body but also partly taken up with food.

Virus, bacteria, fungi, animals and plants produce enzymes too and humans learned soon to benefit from these:

• Fermentation of grape juice to wine is only possible because of a special enzyme from the yeast that produces alcohol out of sugar.
• Bread dough can only come up, because yeasts provide the relevant enzymes.
• Sauerkraut is fermented cabbage by various lactic acid bacteria which is formed when the bacteria ferment sugars to lactic acid in the fresh cabbage.
• Cheese: Rennet is a natural complex of enzymes produced in any mammalian stomach to digest mother’s milk. Rennet contains a Proteolytic enzyme (protease) that coagulates the milk, causing it to separate into solids (curds) and liquid (whey). Rennet remains the most popular way of “starting” cheese.

Endogenous enzymes

Digestion:

For example during digestion, intestinal cells produce alimentary enzymes, which split the food into such small molecules so they can be absorbed into the blood. These enzymes include Trypsin, Chymotrypsin, Amylase, Lipases, Pepsin, Sucrase, Maltase, etc.

Inflammation:

During an inflammation, proteolytic enzymes are produced by neighbouring cells, so that the blood clotting process can happen and to remove destroyed tissue. Different enzymes are involved in the process: the enzyme Thrombin, which is important for blood clotting or Elastase, a proteolytic enzyme, involved in tissue degradation.

Exogenous Enzymes

Ingested enzymes (from plants, animals, bacteria and fungi) are absorbed in a small amount of our gut and attain the blood, where they have some effects.

It is therefore not amazing that treatment with enzymes is used since thousands of years in different cultures – even nobody knows how it works.

Some examples:

1. Chewed leaves from Ficus (high in the enzyme Ficin) were used to support healing of wounds (this effect is already mentioned in the Bible).
2. Minced Ficus leaves in water were given – until today – to domestic animals to fight worm infections and 2004 Konno provided evidence that Ficin, a protease in the leaves is responsible for this effect.
3. Native people in South and Central America use Pineapple juice to treat chronic inflammations, wound infections and to support wound healing.
4. Since about 60 years, (see “History of Enzyme Therapy”) therapy with enzymes from plants (e.g. Bromelain, Papain), animals (e.g. Pancreatin), are used in the treatment of disease, especially inflammatory diseases.

Konno K, Hirayama C, Nakamura M, Tateishi K, Tamura Y, Hattori M, and Kohno K. Papain protects papaya trees from herbivorous insects: role of cysteine proteases in latex. Plant J 37 (4):370-378, 2004.

Many plants contain latex that exudes when leaves are damaged, and a number of proteins and enzymes have been found in it. The roles of those latex proteins and enzymes are as yet poorly understood. We found that papain, a cysteine protease in latex of the Papaya tree (Carica papaya, Caricaceae), is a crucial factor in the defense of the papaya tree against lepidopteran larvae such as oligophagous Samia ricini (Saturniidae) and two notorious polyphagous pests, Mamestra brassicae (Noctuidae) and Spodoptera litura (Noctuidae). Leaves of a number of laticiferous plants, including papaya and a wild fig, Ficus virgata (Moraceae), showed strong toxicity and growth inhibition against lepidopteran larvae, though no apparent toxic factors from these species have been reported. When the latex was washed off, the leaves of these lactiferous plants lost toxicity. Latexes of both papaya and the wild fig were rich in cysteine-protease activity. E-64, a cysteine protease-specific inhibitor completely deprived the leaves of toxicity when painted on the surface of papaya and fig leaves. Cysteine proteases, such as papain, ficin, and bromelain, all showed toxicity. The results suggest that plant latex and the proteins in it, cysteine proteases in particular, provide plants with a general defense mechanism against herbivorous insects.