Dimethylallyltryptophan synthase

Unsold lA, LiSM, Overproduction, purification and characterization of FgaPT2, a dimethylallyltryptophan synthase from Aspergillus fumigatus, Microbiology... 

Tsai H-F, Wang H, Gebler JC, Poulter CD, Schardl CL. The Claviceps purpurea gene encoding dimethylallyltryptophan synthase, the committed step for ergot alkaloid biosynthesis. Biochem Biophys Res Commun 216 119-125, 1995. 

Gebler JC, Poulter CD. Purification and characterization of dimethylallyltryptophan synthase from Claviceps purpurea. Arch Biochem Biophys 296 308-313, 1992. 

Chemoenzymatic synthesis. As for other indole positions, enzymatic prenylation appears to become competitive. Li employed the 4-dimethylallyltryptophan synthase FgaPT2 [211] and the 7-dimethylallyltryptophan synthase DM ATS [212] (both from Aspergillus fumigatus) to prenylate tryptophan derivatives (286) on the 100 nanomolar scale. In all cases shown in Scheme 54, yields >90% were obtained overnight, based on recovered starting material. As coupling partner, ammonium prenylpyrophosphate (8) was used as always. 

Scheme 54 Chemoenzymatic 4- and 7-prenylations of tryptophan derivatives 286 (FgaPT2 4-dimethylallyltryptophan synthase, DMATS 7-dimethylallyltryptophan synthase from Aspergillus fumigatus) by Li and co-workers [211, 212]...

The end-product repression involves probably the blockage of formation of specific synthases, at the time of a maximum rate of secondary biosynthesis. This results in a gradual decline in the level of the enzyme and a retardation of the product formation. The phenomenon was observed in gramicidin S synthases by Bacillus brevis (30), bacitracin synthase in Bacillus licheniformis (31), anhydrotetracycline hydratase by treptomyces aureofaci-ens (4), novobiocic acid synthase in Streptomyces niveus (35) or dimethylallyltryptophan synthase by ciaviceps (33). 

Four enzymes which are involved in the biosynthesis of the ergot alkaloids have now been isolated from Claviceps. The other three are 4-dimethylallyltryptophan synthase , chanoclavine-I cyclase , and agroclavine hydroxylase . ... 

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