EXPRESSION OF GENES aroG AND pheA IN PHENYLALANINE BIOSYNTHESIS
苯丙氨酸合成的关键酶基因aroG与pheA串联表达

aroGand pheAgenes,encoding 3 Deoxy D arabinoheptulonate 7 phosphatesyn thase(DS) and Chorismate mutase (CM) prephenate dehydratase(PD) in the pathway of phenylalnine biosynthesisrespectively,were amplified by polymerase chain reaction(PCR) .The genes were assembled on the multicopy vectors and expressed in both Escherichia coli and Brevibacterium .The productsoftwogene weredetected by SDS PAGE.Theactivities ofrelevantenzymes were measuredinthecrudeextractofthe hoststrain. When aroG pheA genes wereintroducedinto E.coli p2392 ,the activities of DS,CMand PDwereincreased by 4 .3 fold,4 .4 fold and 2.2 fold respectively. Whereas in the case of Brevibacterium flavum 2732,the activitiesof DS,CMand PDwereincreased by 12.3 fold,2.3 fold and 5 .6 fold,respectively. As the results,the overproduction of phenylalanine was brought about by using the geneticengineeringstrain of B.flavum .