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A novel protein tyrosine phosphatase like phytase from Lactobacillus fermentum NKN51: Cloning, characterization and application in mineral release for food technology applications

Sharma, Rekha, Kumar, Piyush, Kaushal, Vandana, Das, Rahul, Kumar Navani, Naveen
Bioresource technology 2018 v.249 pp. 1000-1008
Eleusine coracana, Lactobacillus fermentum, active sites, bioavailability, durum wheat, feeds, food technology, gastrointestinal system, ionic strength, ions, nutritive value, pH, phytases, phytic acid, probiotics, protein-tyrosine-phosphatase, temperature
A novel protein tyrosine phosphatase like phytase (PTPLP), designated as PhyLf from probiotic bacterium Lactobacillus fermentum NKN51 was identified, cloned, expressed and characterized. The recombinant PhyLf showed specific activity of 174.5 U/mg. PhyLf exhibited strict specificity towards phytate and optimum temperature at 60 °C, pH 5.0 and ionic strength of 100 mM. Kₘ and Kcₐₜ of PhyLf for phytate were 0.773 mM and 84.31 s⁻¹, respectively. PhyLf exhibited high resistance against oxidative inactivation. PhyLf shares no homology, sans the active site with reported PTLPs, warranting classification as a new subclass. Dephytinization of durum wheat and finger millet under in vitro gastrointestinal conditions using PhyLf enhanced the bioaccessibility of mineral ions. Probiotic origin, phytate specificity, resistance to oxidative environment and gastric milieu coupled with ability to release micronutrients are unique properties of PhyLf which present a strong case for its use in ameliorating nutritional value of cereals and animal feed.