Premium
Rhodanese Activity of Soils
Author(s) -
Tabatabai M. A.,
Singh B. B.
Publication year - 1976
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1976.03615995004000030023x
Subject(s) - rhodanese , chemistry , soil water , toluene , kinetics , reaction rate constant , activation energy , arrhenius equation , specific activity , chromatography , enzyme , biochemistry , organic chemistry , biology , ecology , physics , quantum mechanics
The detection of rhodanese (enzyme catalyzes the formation of SCN ‐ from S 2 O 3 2‐ and CN ‐ ) in soils is reported, and a simple method of assaying rhodanese activity in soils is described. This method involves colorimetric determination of the SCN ‐ produced by rhodanese activity when soil is incubated with buffered (0.05 M THAM, pH 6.0) S 2 O 3 2‐ and CN ‐ solutions and toluene at 37°C for 1 hour. The method developed is rapid, sensitive, and precise. The procedure used to extract SCN ‐ stops rhodanese activity in soils and gives quantitative recovery of the SCN ‐ formed. Results showed that steam sterilization and formaldehyde inhibit, sulfate and chloride activate, and toluene has no effect on rhodanese activity in soils. The initial rates of SCN ‐ formation obeyed zero‐order kinetics; in one soil, the rate slowed with time of incubation. The temperature dependence of the rate constant conformed to the Arrhenius equation up to the point of enzyme inactivation (65°C). The activation energy of rhodanese activity of the eight soils studied ranged from 5,160 to 8,110 (avg. 6,690) calories/mole. Studies of other properties of rhodanese activity in soils are reported.