Studies In Enzyme Make-up of Vibrio cholerae: Part XII-Ribonuclease Activity

Abstract

Ribonucleic acid depolynlerizing activity in certain cell-free preparations and resting cell suspensions of Vibrio cholerae has been Investigated.Though the intact cells are entirely inactive, crude extracts obtained by grinding the cells with glass powder and extracting with 0·9 per cent potassium chloride solution are highly active. More than 68 per cent of the activity has been found associated with supernatants obtained by centrifugation at 73,400 g. The sedimented particulate rnatertal also possesses appreciable activity. Depolymerization of RNA by cell-free extracts is optimum at pH 8·0. The reaction is very strongly inhibited by copper ions and to a lesser extent by EDTA and 8-hydroxyquinoline. The enzyrne in cell-free extracts is inactivated by heating. The activity does not vary appreciably in the crude cell extracts of different antigenic strains of V. cholerae.