Synthesis of Galloyl-Coenzyme A Thioester
نویسنده
چکیده
Galloyl-Coenzyme A, 4-0-/?-D-Glucosidogalloyl-Coenzyme A, Thioester, 4-0-/?-D-Glucosidogalloyl Hydroxamic Acid, N-Succinimidyl 4-0-/?-D-Glucosidogallate, Gallotannins Galloyl-CoA, a potential intermediate in the biosynthesis of gallotannins, has been prepared via N-succinimidyl 4-0-/?-D-glucosidogallate and 4-0-/?-D-glucosidogalloyl-CoA. Besides a major absorption band at 261 nm, the UV-spectra of the purified thioester and its corresponding 4-O-glucoside contain a longer wavelenght absorption band due to the thioester linkage at 305 nm (galloyl-CoA) or at 290 nm (shoulder, glucosidogalloyl-CoA). The molar extinction coefficients e of the two thioesters were determined via the iron-complex of 4-0-/?-D-glucosidogalloyl hydroxamic acid; e261-values of 19.5 x 10® [cm2 m ol-1] and 21.5 x 10® [cm2 mol-1] were calculated for galloyl-CoA and its glucoside, respectively. Difference spectra, i.e. absorbance before esterolysis and after, revealed maximal absorption o f the thioester bond at 310 nm (zfe = 7.4x 106 [cm2 mol-1]) for galloyl-CoA and at 282 nm {Ae = 1 . 2x 106 [cm2 mol-6]) for glucosidogalloyl-CoA. The two thioesters were further characterized by determining their halflifes during hydroxylaminolysis and alkaline hydrolysis.
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