ISOLATION OF A TRYPSIN-SENSITIVE INHIBITOR OF O-ANTIGEN SYNTHESIS INVOLVED IN LYSOGENIC CONVERSION BY BACTERIOPHAGE EPSILON15

Lysogenization of Salmonella anatum by bacteriophage ε{lunate}15 brings about the synthesis of a cellular O-antigen with β-galactosyl linkages in place of the usual α-galactosyl linkages. The α-galactosyl linkages are generated by a host enzyme which polymerizes trisaccharide units into O-antigen. Recent work has shown that after infection with ε{lunate}15, host α-polymerizing activity rapidly disappears and is replaced by a new bacteriophage enzyme which generates a β-galactosyllinked polymer. I have isolated a trypsin-sensitive factor which specifically inhibits the host α-polymerizing enzyme but not the phage β-polymerizing enzyme, and which is present in both newly infected and lysogenic cells. This inhibitor is probably responsible for the loss in α-polymerizing activity following infection. © 1969.