Interactions between phytases and soil constituents: implications for the hydrolysis of inositol phosphates.

This chapter reviews the interactions of phytases with soil constituents and considers the implications of this for the hydrolysis of inositol phosphates in soil. Emphasis is given on the impacts of the soil environment on the stability and catalytic efficiency of discrete phytase proteins following their release from the cytoplasm. The various factors affecting phytase activity in soil are also discussed. These are: (i) deactivation and inhibition by adsorption and immobilization on soil solid particles; (ii) proteolytic and microbial mediated degradation; (iii) inhibition by interaction with metal ions, anions and metabolites; and (iv) denaturation by soil environmental factors (temperature, pH, water content and light).