'modified aspergillus fumigatus phytase with an improved specific activity and food or food composition'.

摘要

Patent: Modified phytases. The present invention relates to a process for the production of a modified phytase with enhanced activity properties, characterized in that the following steps are performed: a) the three-dimensional structure of the phytase to be modified and, optionally, of another phytase with activity properties that are more favorable than those of the phytase to be modified is computer modeled based on the three-dimensional phytase structure of mu aspergillus niger mv; (b) the structure of the phytase active sites to be modified and the phytase with the most favorable activity properties are compared and those amino acid residues at both different active sites are identified; c) an adn sequence encoding a modified phytase is constructed by modifying nucleotides encoding at least one of the amino acids by which both active sites differ; d) integrating such an adn sequence into a vector capable of expression in a suitable host cell; e) transforming a suitable host cell by the adn sequence of c) or vector d), growing said host cell under suitable growth conditions and isolating the modified phytase from the host cell or culture medium by processes known in the prior art. The present invention further relates to the modified phytase obtained or obtainable by such a process, the DNA sequence encoding this phytase, the vector comprising such DNA sequence, the host cell transformed by such DNA sequence, and a food or feed. food composition comprising this phytase.