Beta-Glucosyltransferase, also called BGT, is a DNA-modifying enzyme. It is encoded by a number of bacteriophages belonging to the T-even group. It catalyses the transfer of glucose (Glc) from uridine diphosphoglucose (UDP-Glc) to 5-hydroxymethylcytosine (5-HMC) in double-stranded DNA. BGT shows little DNA sequence specificity but modify only 5-HMC bases. The glucosylation protects the infecting viral DNA from host nucleases. In addition to its protective role, the glucosylation has also been implicated in the control of phage-specific gene expression by influencing transcription in vivo and in vitro.