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Urease Activity on a Clay‐Organic Complex
Author(s) -
Boyd Stephen A.,
Mortland Max M.
Publication year - 1985
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/sssaj1985.03615995004900030018x
Subject(s) - chemistry , urease , adsorption , clay minerals , ammonium , organic matter , hydrophobic effect , enzyme , thermal stability , substrate (aquarium) , inorganic chemistry , chromatography , organic chemistry , mineralogy , ecology , biology
Urease may be adsorbed on hexadecyltrimethyl‐ammonium (HDTMA)‐smectite by hydrophobic bonding. This mechanism is independent of pH and results in enzyme activity ash igh as that in homogenous solution. As much as forty percent by weight of enzyme can be bound to the clay‐organic complex before free enzyme appears in the supernatant solution. Several cycles of washing the enzyme‐clay‐organic complex at the 10% by weight level did not result in any enzyme removal. The free and bound enzyme behaved similarly with respect to kinetic parameters, pH optimum, and selectivity for substrate. Thermal stability and resistance to proteolysis were greatly decreased for urease immobilized on HDTMA smectite as compared with homogenous solution. In soils, enzymes may be immobilized on natural clay‐organic matter complexes by hydrophobic bonding.