The present invention relates to barley isolated polypeptides having phytase activity, recombinant DNA sequences encoding such polypeptides, methods of producing such polypeptides and the use of said polypeptides in transgenic plants. The invention disclose polypeptides having affinity for the substrate phytate (1,2,3,4,5,6 myo-inositol-hexakisphosphate, phytic acid), comprising an amino acid sequences as described by the invention. Furthermore, the invention discloses DNA fragments encoding said polypeptides, and cDNA fragments encoding said polypeptides. The polypeptides of the invention may for example be used as an additive in animal feeds, an additive in food for human consumption or to extract proteins from rice bran. The invention also concerns a transgenic plant or part thereof, wherein said plant or part thereof have been genetically modified to comprise a polypeptide as defined in by the invention.