Active Site

Galactose-1-phosphate uridyl transferase, class I His-active site (IPR019779)

Short name: GalP_UDPtransf1_His-AS


Galactose-1-phosphate uridyl transferase EC: (galT) catalyses the transfer of an uridyldiphosphate group on galactose (or glucose) 1-phosphate. During the reaction, the uridyl moiety links to a histidine residue. In the Escherichia coli enzyme, it has been shown [PMID: 2845364] that two histidine residues separated by a single proline residue are essential for enzyme activity. The first one is a ligand to a zinc ion and the second act as a nucleophile (and an active site).

On the basis of sequence similarities, two apparently unrelated families seem to exist. Class-I enzymes are found in eukaryotes as well as some bacteria such as E. coli or Streptomyces lividans, while class-II enzymes have been found so far only in bacteria such as Bacillus subtilis or Lactobacillus helveticus [PMID: 2066342].

This entry represents the active site residues of the class-I enzymes.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns