Determining soil enzyme location and related kinetics using rapid fumigation and high-yield extraction

• Published in: Soil biology & biochemistry Vol. 40; no. 9; pp. 2178 - 2181
• Main Authors: Margon, Alja, Fornasier, Flavio
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01.09.2008; New York, NY Elsevier Science
• Subjects: Adsorption; Agronomy. Soil science and plant productions; arylsulfatase; Biochemistry and biology; biogeochemical cycles; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; cytolysis; enzyme activity; enzyme kinetics; Extraction; Fumigation; Fundamental and applied biological sciences. Psychology; humic substances; Kinetics; Location; methylene chloride; phosphomonoesterases; Physics, chemistry, biochemistry and biology of agricultural and forest soils; soil biological properties; Soil enzymes; soil fumigation; soil microorganisms; Soil science; spatial variation; Soil enzymes; Extraction; Fumigation; Kinetics; Adsorption; Location; Soils; Enzyme; Yield; Soil science
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2008.02.006

Knowledge concerning the location of soil enzymes and their kinetics is necessary for a better understanding of their roles in biogeochemical cycles. A rapid dichloromethane fumigation procedure and a new extraction method giving negligible co-extraction of humic substances were used. Fumigation and consequent cell lysis increased the activity of arylsulfatase, but not that of acid and alkaline phosphomonoesterase, suggesting that only the former enzyme was located both extracellularly and intracellularly. Extracted arylsulfatase displayed a Michaelis–Menten constant ( K m) significantly lower than in fumigated soil, which in turn was significantly lower than in unfumigated soil. In contrast, each phosphomonoesterase displayed the same K m in extracts, fumigated and unfumigated soils. These results show that activity of soil phosphomonoesterases is not influenced by any direct interaction with soil and, therefore, are more likely to be extracellular enzymes primarily devoted to biogeochemical cycling than are arylsulfatases.