Biochemical properties and substrate specificities of alkaline and histidine acid phytases

Abstract

Phytases are a special class of phosphatase that catalyze the sequential hydrolysis of phytate to less-phosphorylated myo-inositol derivatives and inorganic phosphate. Phytases are added to animal feedstuff to reduce phosphate pollution in the environment, since monogastric animals such as pigs, poultry, and fish are unable to metabolize phytate. Based on biochemical properties and amino acid sequence alignment, phytases can be categorized into two major classes, the histidine acid phytases and the alkaline phytases. The histidine acid phosphatase class shows broad substrate specificity and hydrolyzes metal-free phytate at the acidic pH range and produces myo-inositol monophosphate as the final product. In contrast, the alkaline phytase class exhibits strict substrate specificity for the calcium-phytate complex and produces myo-inositol trisphosphate as the final product. This review describes recent findings that present novel viewpoints concerning the molecular basis of phytase classification.

Avian multiple inositol polyphosphate phosphatase is an active phytase that can be engineered to help ameliorate the planet's “phosphate crisis”

“…There is also the problem that the widespread use of fungal phytases is increasingly promoting occupational asthma and rhinitis (Baur et al, 2002). Phytase also deteriorates during its exposure to the high temperatures involved in feed processing, limiting its effectiveness (Oh et al, 2004;Haefner et al, 2005;Ullah et al, 2000).…”

“…These enzymes, when categorized by differences in catalytic mechanisms, fall into four different groups: the "purple acid phosphatase" family, β-propeller phytases, "P-loop" phytases and histidine acid phosphatases (Oh et al, 2004;Lei and Porres, 2003;Mullaney and Ullah, 2003;Chu et al, 2004). The latter is the largest family, which is designated by the RHGXRXP active site.…”

“…All of the cloned enzymes that are widely-recognized to be phytases originate from plants and micro-organisms (Oh et al, 2004;Lei and Porres, 2003;Mullaney and Ullah, 2003). Animal cells do contain InsP 6 (Shears, 2001), and an InsP 6 -phosphatase, namely, the multiple inositol polyphosphate phosphatase, or MINPP (Craxton et al, 1997;Chi et al, 1999).…”

Effect of Beta-propeller Phytase from Pichia pastoris on Energy Partition in Juvenile Litopenaeus vannamei Fed a Plant Protein-Based Diet

“…Most of the commercially available phytases are histidine acid phytases and possess catalytic activity in a pH range 2.5-6.0. The β-propeller phytase FTEII from Bacillus species is an alternative to histidine acid phytases because of its high thermostability, calcium phytate-complex substrate specificity, pH profile, and proteolysis resistance (Oh, Choi, Park, Kim, & Oh, 2004). Several β-propeller phytases, one from B. subtilis (Guerrero-Olazarán, Rodríguez-Blanco, Carreon-Treviño, Gallegos-López, Viader-Salvadó, 2010), and others designed by a structure-guided consensus approach, have been produced by the methylotrophic yeast P. pastoris (Viader-Salvadó, Gallegos-López, Carreón-Treviño, Castillo-Galván, Rojo-Domínguez, & Guerrero-Olazarán, 2010).…”

General Properties of Phytase Produced by Fluorescent Pseudomonas sp. BUN1

“…So far, a variety of phytases have been widely found in plants and microorganisms (Oh et al, 2004). Although two filamentous fungal-derived strains, Aspergillus niger and Aspergillus ficuum are currently available for the commercial production, studies are ongoing to identify more desirable phytases and to induce their over-expression in industrially attractive host, such as yeast or E. coli through recombinant DNA work for animal feed application so as to overcome the defects of the fungal enzyme with regard to substrate specificity and catalytic efficiency (Chi et al, 2009;Huang et al, 2009;Hussin et al, 2007).…”