重芳徑 的英文怎麼說
中文拼音 [zhòngfāngjìng]
重芳徑
英文
heavy aromatics-
4. engineering dhqase ( arod ) - deficient e. coli mutant with a second copy of the arob gene gene targeting technique was used to disrupt the arod gene in e. coli chromosome. the mutant 31bk was engineered, in which homologous recombination of the arobkanr gene cassette into the arod locus ( arod : : arobkanr ) of the e. coli strain atcc31884 genome utilized the helper plasmid pkd46 with red system. the host cell 31bk lacked catalytic activity of dhqase ( arod ) and had a second copy of the arob gene, so it improved carbon flow into the quinic acid biosynthesis direction
構建宿主菌基因精確定位突變株31bk （ arod : : arobkan ~ r ）為了改變代謝途徑脫氫奎尼酸（ dhq ）分支點上的代謝流量，使之充分流向目的產物奎尼酸合成方向，利用基因打靶技術構建了31884宿主菌arod基因精確定位插入突變體，使dhq脫水酶（ dhqase ）失活，阻斷了碳代謝流流向芳香氨基酸生成的方向，同時用同源重組的方法將arob基因定位整合入染色體上，解除了限速酶對碳代謝流通過共同途徑到達dhq的阻遏影響，並減輕代謝負擔。When both genes were co - expressed in e. coli, the activity of ppsa varied from 2. 1 - 9. 1 fold comparing to control, but the activity of tkta was relatively stable ( 3. 9 - 4. 5 fold ). whatever the two genes were expressed respectively or cooperatively, both could promote the production of dahp, the first intermediate of the common aromatic pathway, but co - expression was more effective on forming dahp and screened ppt - and ptp - as more effective. the results demonstrate that co - expression of ppsa and tkta can improve the production of dahp, and what ' s more, when multigenes co - expressed, the recombinant which has coordinated enzymes activity is optimum
莽草酸途徑的最優化和整體調控基因csra的敲除正是上述改變的分子基礎，同時也為三種芳香族氨基酸的基因工程菌的構建打下了基礎; 7 .在國內外首次實現了共同途徑限制性底物關鍵酶ppsa刁無『及arog與分支途徑關鍵酶基因phea的串聯高效表達，所構建的重組質粒ptga ，其ppsa 、 tkta 、 arog 、 cm和pd的酶活分別比對照提高了3 、 2 、 2 ， 5 、 4 、 2 . 3倍，且其酶活比較協調一致; 8 .將ptga導入到篩選的基因敲除和基因替換菌株大腸桿菌31884 c甲b中，搖瓶發酵證實比以往所構建的基因工程菌株具有較高的phe產量和糖轉化率率，分別為0 . 448 %和22 . 4 % 。
分享友人