Purification and Characteristics of Pyocin B39 II. Physical and Chemical Properties

A purified preparation of pyocin B39 was shown to be homogeneous by disc electrophoresis and ultracentrifugation. Pyocin B39 is an antibacterial agent, protein in nature, and is capable of inhibiting the growth of susceptible cells. It caused a susceptible strain ofPseudomonas aeruginosa to release ultraviolet-absorbing material. Pyocin B39 appears to be a protein with a high molecular weight; its sedimentation coefficient is 32.8S . It was destroyed by 7m urea but was resistant to attack by proteolytic enzymes, such as pepsin and trypsin. From its sedimentation coefficient, a molecular weight of about 2 × 106 was calculated. An electron photomicrograph of pyocin B39 revealed it as a rodlike particle, 7.50 pm long and 1.08 pm wide, with striations running at nearly right angles to the axes of the particle.