Hydrolysis of precipitated phytate by three distinct families of phytases

By J. Tang, A. Leung, C. Leung, B. Lim. 2006

138 citations recorded by the source corpus.

While genetically modified plants that secrete histidine acid phosphatases (HAPs), β-propeller phytases (BPPs) and purple acid phosphatases (PAPs) have been shown to assimilate soluble phytate, little is known about whether these plants have the ability to hydrolyze precipitated phytate. In this study, the ability of representative members of these three classes of phytases to hydrolyze metal-phytate salts and to hydrolyze phytate adsorbed to aluminum precipitates was compared. All three phytases were able to hydrolyze Ca2+-, Mg2+-, and Mn2+-phytates, but were unable to hydrolyze Al3+-, Fe2+-, Fe3+-, Cu2+-, and Zn2+-phytates. When these ions were present, the hydrolysis of Ca2+-phytate was prevented. Citrate was more potent than malate and oxalate in solubilizing some of these phytate salts for enzyme hydrolysis. Phytate adsorbed to aluminum precipitates was resistant to all three enzymes, except when organic acids were added (citrate>oxalate>malate). While increasing concentrations of organic acids were inhibitory to enzyme activity (oxalate >citrate>malate), PAP was more resistant to citrate than HAP. As desorption of phytate from a solid surface by organic acids is essential for phytase activity, the genetic engineering of plants that enhances the secretion of both citrate and phytases from the root may be a feasible approach to improving soil phytate assimilation.

Subfields: Plant Science

View Paper: https://www.semanticscholar.org/paper/5235bb8a0b74942474826dafb813a3f93dc667d8

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Citations in the corpus

Plant and microbial strategies to improve the phosphorus efficiency of agriculture (2011, background): “Organic anions improve the mobilisation of organic P in soils and to increase its enzyme-lability, including that of inositol phosphates (Hayes et al. 2000a; Tang et al. 2006; Wei et al. 2010).”
Organic-acid-producing, phytate-mineralizing rhizobacteria and their effect on growth of pigeon pea (Cajanus cajan) (2010, methodology): “Low molecular weight organic acids (OAs), such as citric and malic acids, when added to phytase assay systems stimulate the release of P from insoluble or sparingly soluble phytate salts (Tang et al., 2006).”
Phosphatase and phytase activities in nodules of common bean genotypes at different levels of phosphorus supply (2008, background): “Secreted phytases were unable to release Pi from phytates fixed to various soil components although they could hydrolyze soluble phytates supplied in agar (Tang et al. 2006).”
Solubilization of Phosphorus by Soil Microorganisms (2011, background): “phytate) making it more susceptible to enzymatic hydrolysis (Otani and Ae 1999; Tang et al. 2006).”
Microbial phytase activity and their role in organic P mineralization (2015, background): “Phytases are capable of hydrolyzing the soluble forms of Ca and Mg inositol phosphates, but were incapable in the case of Al, Fe, Cu and Zn inositol phosphates adsorbed to sand (Lung & Lim 2006; Tang et al. 2006; El-Toukhy et al. 2013).”
Feeding hungry plants: The role of purple acid phosphatases in phosphate nutrition (2010, background): “Citrate appears to be the most effective relative to other organic anions, such as malate [5,8].”
Phytases and Phytase-Labile Organic Phosphorus in Manures and Soils (2013, background): “Three phytases differing in catalytic mechanism were able to hydrolyze phytate precipitated with Ca2+, Mg2+, and Mn2+ but not with Al3+, Fe2+, Cu2+, and Zn2+, and even the sole presence of these cations inhibited hydrolysis of precipitated calcium phytate (Tang et al., 2006).”