This reaction is catalyzed by dahp synthase , which in microorganisms is also the target for negative - feedback regulation of the pathway mediated either by the pathway intermediate chorismate , or by endproducts phenylalanine , tyrosine and tryptophan 在大肠杆菌中， arog基因编码受苯丙氨酸反馈抑制的dahp合成酶同工酶arog ，催化e4p和pep反应生成dahp 。
Suaeda liaotungensis kitag is a halophyte with high salt tolerance ability . this research performed a systemic study on betaine , betaine synthetase and the genes encoding betaine synthetase in suaeda liaotungensis 辽宁碱蓬( suaedaliaotungensiskitag )是一种耐盐性很强的盐生植物，本文对其甜菜碱、甜菜碱合成酶、甜菜碱合成酶基因进行了较为系统的研究。
Nitrate is converted to ammonium by nitrate reductase and ammonium is then incorporated into glutamine and gluamate , either by the glutamine synthase - glutamate synthase ( gs - gogat ) pathway or by glutamate dehydrogenase ( gdh ) 硝酸盐在硝酸还原酶作用下被转化为铵，接着所产生的铵在谷氨酰胺合成酶-谷氨酸合酶( gs - gogat )或谷氨酸脱氢酶( gdh )的作用下与谷氨酰胺和谷氨酸结合。
By changing pichia pastoris ' s metabolic path rationally , a constitutive recombinant p . pastoris sibas 5071 with riched sam synthetase was obtained on the basis of research of sulfide ' s metabolism in yeast in our laboratory 本实验室在对酵母细胞中含硫物质代谢研究的基础上，通过合理改造pichiapastoris的代谢通路，获得了一株组成型表达sam合成酶2 ( sams2 )的重组p . pastoris菌株sibas5071 。
( 3 ) uv - b radiation increased the phenylalanina ammonia - lyase ( pal ) activity in leafy thallus of duckweeds , and as a consequence , flavonoids were accumulated . flavonoids synthesis induced by supplementary uv - b is an adaptive response of duckweeks under enhanced uv - b radition ( 3 )紫萍可以通过提高uv - b吸收物质如类黄酮合成酶苯丙氨酸氨裂解酶( pal )活性，促进类黄酮的积累来适应uv - b辐射的胁迫。
The start codon is at 84 - 86bp , the stop codon at 1658 - 1661bp . the homologous comparison of the deduced amino acid sequence with other plant epsp synthase proteins shows the identity to those of b . napus , a . thaliana , tomato , n . labacum respectively are 92 % , 91 % , 80 % , 65 % 同源比较该段序列所编码的氨基酸序列可以发现epsp合成酶有较高的保守性，它与欧洲油菜、拟南芥、西红柿、烟草的同源性分别为920 、 91o 、 80o 、 65o 。
Meanwhile , the results showed that althougt the trehalose was produced successively , the intracellular trehalose concentration was 0 at the end of the reaction . trehalose was excreted to culture medium completely . yeast ' s cell was only as a carrier of the trehalose synthase 利用酵母海藻糖合成酶系合成胞外海藻糖是海藻糖生产方法的一个创新，它结合了酶法和酵母提取法的优点，是利用酵母大量生产海藻糖的又一新的尝试。
