| 摘要 |
A method for modifying the specificity and/or efficiency of an enzyme, while retaining its catalytic activity, characterised in that it comprises: selecting an enzyme, the tertiary structure of which is substantially known or deduced; identifying at least one specificity and/or efficiency-related region; identifying or constructing unique restriction sites bounding the identified region in the DNA coding therefor; generating a DNA sequence which corresponds to at least a portion of the identified region, except that the nucleotides of at least one codon are randomized, or selecting as a substitute for at least a portion of the identified region an alternative such region, which may itself be similarly randomized; using the generated or substitute DNA sequence to replace the original such sequence; expressing the DNA including the generated or substitute DNA sequence; and selecting for a desired modification so that the DNA coding therefor may be isolated is disclosed. |
