A Phytase Characterized by Relatively High pH Tolerance and Thermostability from the Shiitake Mushroom Lentinus edodes

• Published in: BioMed research international Vol. 2013; no. 2013; pp. 1 - 7
• Main Authors: Chen, Qing-Jun, Ng, Tzi Bun, Wu, Ying-Ying, Zhang, Guo-Qing, Wang, He-Xiang
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 01.01.2013; John Wiley & Sons, Inc
• Subjects: 6-Phytase - chemistry; 6-Phytase - isolation & purification; Amino Acid Sequence; Chromatography; Enzyme Stability; Hydrogen-Ion Concentration; Ion exchange chromatography; Molecular Weight; Phosphatases; Physiological aspects; Properties; Shiitake; Shiitake Mushrooms - enzymology; Substrate Specificity; Temperature; China; Hong Kong, China
• ISSN: 2314-6133; 2314-6141; 2314-6141
• DOI: 10.1155/2013/540239

A monomeric phytase with a molecular mass of 14 kDa was acquired from fresh fruiting bodies of the shiitake mushroom Lentinus edodes. The isolation procedure involved chromatography on DEAE-cellulose, CM-cellulose, Q-Sepharose, Affi-gel blue gel, and a final fast protein liquid chromatography-gel filtration on Superdex 75. The purified phytase demonstrated the unique N-terminal amino acid sequence DPKRTDQVN, which exhibited no sequence similarity with those of other phytases previously reported. It expressed its maximal activity at pH 5.0 and 37°C. Phytase activity manifested less than 20% change in activity over the pH range of 3.0–9.0, considerable thermostability with more than 60% residual activity at 70°C, and about 40% residual activity at 95°C. It displayed a wide substrate specificity on a variety of phosphorylated compounds with the following ranking: ATP > fructose-6-phosphate > AMP > glucose-6-phosphate > ADP > sodium phytate > β-glycerophosphate. The phytase activity was moderately stimulated by Ca2+, but inhibited by Al3+, Mn2+, Zn2+, and Cu2+ at a tested concentration of 5 mM.