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B6db references: 92296771

type Journal Article
authors Gebler, J. C.; Poulter, C. D.
title Purification and characterization of dimethylallyl tryptophan synthase from Claviceps purpurea
journal Arch Biochem Biophys
ui 92296771
year (1992)
volume 296
number 1
pages 308-13.
keywords Chromatography, Gel
abstract Dimethylallyl tryptophan synthase (DMAT synthase) catalyzes the alkylation of L-tryptophan by dimethylallyl diphosphate to form 4- (gamma,gamma-dimethylallyl)-L-tryptophan. The enzyme from mycelia of Claviceps purpurea was purified approximately 125-fold to apparent homogeneity by chromatography on n-butyl Sepharose, Q Sepharose, phenyl Sepharose, and Protein Pak as judged by sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE). Analysis by gel filtration chromatography and SDS-PAGE indicated that DMAT synthase is an alpha 2 dimer with a molecular mass of 105 kDa. The purified enzyme was active in metal-free buffer containing EDTA. However, activity was enhanced upon addition of divalent calcium or magnesium ions to the buffer. Values for KM and Vmax were determined in the metal-free EDTA buffer (KMDMAPP, 14 microM; KML-tryptophan, 40 microM; Vmax, 215 nmol min-1 mg-1), 4 mM CaCl2 (KMDMAPP, 8.0 microM; KML-tryptophan, 17 microM; Vmax, 504 nmol min-1 mg-1), and 4 mM MgCl2 (KMDMAPP, 8.0 microM; KML-tryptophan, 12 microM; Vmax, 455 nmol min-1 mg-1). The product was isolated and characterized by 1H NMR, uv, and FAB mass spectrometry.
last changed 2002/11/12 16:17

B6db references