| 摘要 |
The present invention relates to a serine acetyltransferase which exhibits a sensitivity to the L-cysteine inhibitor which sensitivity is reduced in comparison to a wild-type enzyme and whose protein sequence exhibits at least one mutation or deletion when compared with the wild-type sequence, wherein the mutation is in the sequence region of amino acids 97-100, 164-169, 237, 239-240, 245-259 and 267-269 or the deletion is in the carboxy terminal sequence region of amino acids 237-240, 245-259 and 267-269, with position 1 being the start methionine of the Figure 5 (SEQ ID NO: 1) and with the mutation of Met to Ile in position 256 being excluded. The invention further relates to a DNA sequence that encodes serine acetyltransferase, microorganisms that possess a cysteine metabolism deregulated by at least one above indicated DNA sequence, and a process for preparing O-acetylserine, L-cysteine and compounds derived from L-cysteine, which preparation process is characterized by cultivation of the above mentioned microorganisms in a nutrient medium. |
