Amino acid sequence of the tryptic peptide containing the catalytic-site thiol group of bovine liver uridine diphosphate glucose dehydrogenase

Abstract

The catalytic-site thiol groups of UDP-glucose dehydrogenase from bovine liver were carboxymethylated with iodo[2-14C]lacetate or with iodoacetamidofluorescein. After the residual thiol groups were carboxymethylated with iodoacetate, the proteins were digested with trypsin. The 14C-labeled peptide from the carboxymethylated enzyme was purified to homogeneity by successive thick-layer chromatography on silica gel, paper electrophoresis and chromatography, and column chromatography on Bio-Gel P-6. Homogeneous fluoresceincarboxamidomethylated peptide was prepared from a tryptic digest of fluoresceincarboxamidomethylated enzyme by specific adsorption-desorption from Sephadex G-25. The sequence of either peptide determined by the manual Edman dansyl procedure is: Ala-Ser-Val-Gly-Phe-Gly-Gly-Ser-Cys-Phe-Glx-Glx-Gly-Lys.