Purification and properties of phage P22-induced lysozyme.

Phage P22 induces a lysozyme in Salmonella typhimurium cells toward the later stage of its multiplication. P22 lysozyme has been purified about lOOO-fold starting from the lysate of C1 (clear plaque-forming mutant of phage P22)infected cells. The enzyme has an optimum pH between 7 and 8 and its activity is dependent on the ionic strength of the assay medium. Salts like MgCl,, NaCI, and KC1 are inhibitory to the lysozyme, Gram-negative cells act as better substrates for the lysozyme than do gram-positive cells The enzyme has a molecular weight of about 2 X lo4 and’ rapidly looses its activity at temperatures higher than 40”. The properties of P22 lysozyme have been compared with those of X and T4 lysozymes. All three lysozymes have more or less the same molecular weight and have similar properties although P22 and T4 lysozymes seem to be closer than P22 and X lysozymes.