Table 2: Conditions for assay of soil enzyme activities and their role in soil biogeochemical functioning.

Class/EC number Recommended name Role in soil function Assay conditions
ReactionSubstrateOptimum pH

C cycling
 3.2.1.21 -GlucosidaseCellulose degradation, produces glucose needed by plants and microorganismsGlucoside-R + H2O Glucose + R–OHp-Nitrophenyl- -D-glucopyranoside (10 mM)6

C and N cycling
 3.2.1.30 -GlucosaminidaseChitin degradation, produces amino sugars, one of the major sources of mineralizable NR-N-acetyl- -D glucosaminide R–OH + N-acetyl- -D-glucosaminidep-Nitrophenyl-N-acetyl- -D-glucosaminide (10 mM)5.5

P cycling
 3.1.3.2Acid PhosphataseProduces plant available phosphates, predominant in acid soilsRNa2PO4 + H2O R–OH + Na2HPO4p-Nitrophenyl-phosphate (10 mM)6.5
 3.1.3.1Alkaline PhosphataseProduces plant available phosphates, predominant in alkaline soilsRNa2PO4 + H2O R–OH + Na2HPO4p-Nitrophenyl-phosphate (10 mM)6.5
 3.1.4.1PhosphodiesteraseProduced from plants, animals, and microorganismsRNa2 2PO4 + H2O RNa2PO4 + R–OHbis-p-nitrophenyl phosphate (10 mM)8

S cycling
 3.1.6.1ArylsulfataseProduces plant available sulfatesPhenol sulfate + H2O phenol + sulfatep-Nitrophenyl-sulfate (10 mM)5.8