Microorganisms may be described and characterized by their biochemical/metabolic functions, including their use of enzymes. Here are some terms to know.
Extracellular enzymes (exoenzymes). As the name suggests, exoenzymes act on substances outside of the cell (or extracellular). Keep in mind these simple organisms may not be able to have complex materials pass through the membrane/wall and into the cell itself. Instead, enzymes are excreted so that the break-down can occur outside of the cell. Then the more basic/simpler material building-blocks may then be transported into the cell. Exoenzymes are mostly hydrolytic (reduce complex materials into much simpler building blocks via water “hydro” molecule and “lysis” which means break apart).
- Starch hydrolysis.
- Lipid hydrolysis.
- Casein hydrolysis.
- Gelatin hydrolysis.
Intracellular enzymes (endoenzymes). These enzymes act within the cell. Mostly, they aid in taking the simple building blocks and synthesizing those into useful products.
- Carbohydrate fermentation.
- Litmus milk reactions.
- Hydrogen sulfide production.
- Nitrate reduction.
- Catalase reactions.
- Urease test.
- Oxidase test.
- IMViC (Indole, Methyl red, Voges-Proskauer, Citrate utilization).
- Triple sugar-iron test.
Reference
Cappuccino, J. G., & Welsh, C. (2018). Microbiology: A laboratory manual.
