| 摘要 |
PROBLEM TO BE SOLVED: To obtain novel glutaminase, stable over a wide pH range, high in heat resistance and useful for production of soy sauce, miso or the like, by providing it with specific properties. SOLUTION: This glutaminase has the following properties; function: acting on L-glutamine to produce L-glutamic acid; optimum pH: approximately 8.5; pH range in which it is stable: 3 to 11, when incubated at 4 deg.C for 24 h; optimum working temperature: approximately 50 deg.C, when measured at pH 8.0; temperature at which it is stable: 45 deg.C or lower, when incubated at pH 8.0 for 30 min; and molecular weight: approximately 73,000, determined by gel permeation. It is preferable that this glutaminase has an amino acid sequence of amino acids 34 to 703 in the sequence shown by the formula, and that it is produced by culturing the host cell genetically transformed by a manifestation vector containing DNA coding for the glutaminase. |
