Numerous enzymes participate in their function, particularly lysozyme, whose digestion of the cell wall allows their release upon assembly.   
In their experiments Lederberg and Zinder discovered one that was coded for by the p-h-e+ and the t-r-p+ genes.  The greatest family of them known to exist is the T-even group, and the first to be discovered, T2, was from this family.  Numerous enzymes participate in their function, particularly lysozyme, whose digestion of the cell wall allows their release upon assembly.   These substances are known to mediate one specific type of recombination, transduction.  First identified in the Hershey-Chase blender experiment, FTP, name this class of bacteria-infecting viruses.
In their experiments Lederberg and Zinder discovered one that was coded for by the p-h-e+ and the t-r-p+ genes.  
bacteriophage