Where Do Enzymes Come From?

Enzymes have been isolated from every  type of living organism. Many of these biological catalysts are significant only from an  academic or medical standpoint, but some of the available enzyme from this vast repertoire have been utilized for agricultural and industrial purposes for years. The table below lists several of the industrially on sequential enzymes and their sources in nature. It is significant to note that animals plants and microorganisms all yield industrially important enzymes. Some enzymes of animal or plant origin have been used in agricultural applications;  however, those enzymes most broadly used are of microbial origin.

Source of Enzyme
PLANT
Malted grains or tubers Amylase
Pineapple Bromelin (Protease)
Fig Tree Ficin (Protease)
Papaya Papain (Protease)

ANIMAL
Liver Catalase (Peroxide Breakdown)
Calf Stomach Rennet/Chymosin (Milk Clotting)
Hog Stomach Pepsin (Protease)
Hog Pancreas Pancreatic Enzymes (Several)
Digestive Tract Trypain (Protease)

MICROBIAL
Fungi (Molds and Yeast) amylase, beta glucanase, hemicellulase, protease, cellulase, pectinase, lipase, (many types of each), lactase

BACTERIA
Amylase, protease, isomerase, lactase (many types of each), rennet, oxidase, catalase, beta-glucanase, hemicellulase.

*While enzymes for diagnostic or medical purposes are most important for the benefit  of  thousands of  patients yearly,  their discussion is beyond the scope of this article.

One encounters many digestive  or  hydrolyzing enzymes in the digestive tract of human and other animals. These biological catalysts are necessary for the full utilization of foods ingested. Microorganisms, many being as small as 1/10,000th of an inch in length, are much too minute to have complicated digestive systems as animals do. Therefore, these microbes must predigest their potential foods outside of their cell boundaries so that they can absorb the very small nutrient compounds of predigested foods.

In order to predigest  the potential food sources outside their cell boundaries, many microbes excrete enzymes out through their enveloping membrane with its supportive cell wall and into the surrounding environment. Since these "extra-cellular enzymes" must function in the environment outside the protection of the cell's wall and membrane, they must be reasonably stable and have relatively high resistance to chemicals and must function over a relatively broad temperature range. To realize the effects of the enzymes they produce, microorganisms also must produce relatively large quantities of these catalysts. All of these factors contribute to the industrial significance and durability of extra-cellular microbial enzymes.

It should be noted that most of the agriculturally and industrial important enzymes, are those that catalyze the digestion or "hydrolysis" of certain large organic molecules like starch, cellulose, and protein. The enzymes actually attack these complex molecules, accelerating their digestion and yielding simpler substances. Since this process of  digestion is referred to as hydrolysis, the enzymes that catalyze the process are considered to be "hydrolyzing enzymes" or "hydrolases".

The hydrolyzing enzymes include:

(1) Amylases, which catalyze the digestion of starch into small segments of multiple sugars and into individual soluble sugars.

(2) Proteases, (or proteinase), which split up proteins into their component amino acid building blocks.

(3) Lipase, which split up animal and vegetable fats and oils into their component part: glycerol and fatty acids.

(4) Cellulase (of various types) which breaks down the complex molecule of cellulose into more digestible components of single and multiple sugars.

(5) Beta-glucanase, (or gumase) which digest one type of vegetable gum into sugars and / or dextrins.

(6) Pectinase which digests pectin and similar carbohydrates of plant origin.