ACTION OF TETRADECYLTRIMETILAMMONIUM ON THE PRODUCTION AND KINETIC BEHAVIOUR OF DIFFERENT PHOSPHOLIPASE C OF P. aeruginosa.

GARCÍA, V.; LIFFOURRENA, AS; LISA, AT; LUCCHESI, GI

Córdoba

Jornada; XIII Jornadas Científicas de la Asociación de Biología de Córdoba; 2001

Sociedad de Biología de Córdoba

P. aeruginosa produces two secreted phospholipase C  enzymes, one is hemolytic (PLC-H) and the other is non hemolytic (PLC-N). The expression of both PLCs is regulated  by Pi and choline. PLC-N is always detected during the growth of P. aeruginosa under low-Pi conditions. PLC-H is induced under high-Pi with choline and in low-Pi without choline. In this work we show the action “in situ” and “in vitro” of  TDTMA upon P. aeruginosa PLCs. Supernatant from cultures of low or high-Pi-choline plus 10mg/l of TDTMA exhibited aproximately fivefold-lower PLC-H activity than those from culture without detergent. Pi-low dependent PLC-H expression was not affected by TDTMA. These data indicate the TDTMA is a specific agent that affects only PLC-H induced by choline. PLC-H induced by choline was purified. Kinetic studies performed utilizing artificial substrate indicated that until 60mM, TDTMA behaves as pure competitive inhibitor. PLC, induced by low-Pi medium without choline, was not inibited “in vitro” by TDTMA.    It would be argued the TDTMA is a specific agent which permits to distinguish two PLCs-H of  P. aeruginosa.