Requirements for catalysis in mammalian glycogenin.

ABSTRACT: Glycogenin is a glycosyltransferase that functions as the autocatalytic initiator for the synthesis of glycogen in eukaryotic organisms. Prior structural work identified the determinants responsible for the recognition and binding of UDP-glucose and the catalytic manganese ion and implicated two aspartic acid residues in the reaction mechanism for self-glucosylation. We examined the effects of substituting asparagine and serine for the aspartic acid residues at positions 159 and 162. We also examined whether the truncation of the protein at residue 270 (delta270) was compatible with its structural integrity and its functional role as the initiator for glycogen synthesis. The truncated form of the enzyme was indistinguishable from the wild-type enzyme by all measures of activity and could s

SUBMITTER: Hurley TD 

PROVIDER: S-EPMC1266300 | biostudies-literature | 2005 Jun

REPOSITORIES: biostudies-literature