Distinctive electrophoretic patterns of esterases from Klebsiella pneumoniae, K. oxytoca, Enterobacter aerogenes and E. gergoviae.

Esterases of 14 strains of Klebsiella pneumoniae, 14 strains of K. oxytoca, 16 strains of Enterobacter aerogenes and 16 strains of E. gergoviae were analysed by horizontal electrophoresis in polyacrylamide-agarose gel. Four principal esterase bands (designated E1 to E4) and nine minor bands differing in their activity towards synthetic substrates and in their sensitivity to heat and to di-isofluoropropyl phosphate were defined. The comparative distribution of bands showed that the four species analysed were characterized by distinct electrophoretic patterns of their esterases. Band E1 was found in all four species, bands E2 and E3 only in K. oxytoca and band E4 only in some strains of E. gergoviae. The apparent molecular weights of esterases E2 and E3, determined by electrophoresis in a 4 to 30% polyacrylamide gradient gel, were 58000 (+/- 1000) and 72000 (+/- 1800), respectively.