Comparison of Three Methods for the Purification of the Delta Haemolysin of Staphylococcus aureus

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Abstract
Three methods for the purification of S. aureus delta hemolysin were compared (Kantor et al., 1972; Kreger et al., 1971; Heatley, 1971). The products of these purifications from the culture supernatant of S. aureus strain RN25 were compared by electrophoresis, amino acid analysis, amino-terminal sequence analysis and TLC. The method of Heatley (1971) was superior in terms of recovery and purity of the product. Delta hemolysin prepared by the method of Kreger et al. (1971) could not be sequenced successfully prior to treatment aimed at the removal of the N-formyl group at the amino-terminus. Delta hemolysin appears to exist in 2 distinct molecular forms, one with N-formylmethionine and the other with un-formylated methionine in the amino-terminal position. The former polypeptide species is purified preferentially by the method of Kreger et al. (1971). TLC of the products of each method of purification revealed that they were all heterogeneous, although the major component from the product of the method of Heatley (1971) represented not less than 70% of the product.