ppsa 中文意思是什麼
ppsa
解釋
泛太平洋外科協會-
Ppsa and tkta are the key genes in central metabolism of aromatic amino acids biosynthesis. ppsa encoding phosphoenolpyrucate synthetase a ( ppsa ) which catalyzes pyruvate into pep ; tkta encoding transketolase a which plays a major role in erythrose - 4 - phosphate ( e4p ) production of pentose pathway
Ppsa基因編碼磷酸烯醇式丙酮酸合成酶a （ ppsa ） ，該酶催化丙酮酸合成磷酸烯醇式丙酮酸； tkta基因編碼轉酮酶a ，該酶在磷酸戊糖途徑中生成4 -磷酸赤蘚糖起主要作用。 -
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 % 。 -
We amplified ppsa and tkta from e. coli k - 12 by pcr and constructed recombinant plasmids of them in pbv220 vector containing prpl promoter. because of each gene carrying pl promoter, four productions of ligation were obtained, that are ppt -, ppt -, ptp -, and ptp -. the results of sds - page demonstrated that the bands at 84kd and 73kd were more intensive than the same ones of the controls
3 .從大腸桿菌中克隆了莽草酸途徑關鍵酶基因aro刁、 aroc 、 arob及整體代謝調控基因csra及其側翼序列;從質粒pet28a中克隆了kan抗性基因; 4 .構建了基因盒子aroaar口carobkan ，在其前面加入了強啟動子ptac ，初步證明了pta 。
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