Soil Enzymes

Nutrient cycling in soils involves biochemical, chemical, and physiochemical reactions, with the biochemical processes being mediated by microorganisms, plant roots, and soil animals. Enzymes are denatured by elevated temperature and extreme pH. The two most remarkable properties of enzymes are their specificity and catalytic efficiency, and it is in these properties that enzymes differ most strikingly from simple catalysts. Temperature affects enzyme activity in various ways; the number of factors controlling the effect of pH on an enzyme-catalyzed reaction is even greater. The subject of enzyme inhibition requires special consideration, because soils receive a variety of organic and inorganic chemicals. Soil is a living system where all biochemical activities proceed through enzymatic processes. The solutions of the substrates used for assay of phosphomonoesterases and phosphodiesterase are stable for several days if stored in a refrigerator. The activities of several other enzymes have been detected in soils and methods have been developed for their assays.