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S D ELLIOTT

Publications and source records attributed to S D ELLIOTT.

15 recordsLinked to original sources
PubMed1960

Type and group polysaccharides of group D streptococci.

Polysaccharides extracted from cell walls of 4 serological types of Group D streptococci were serologically type-specific. Acid hydrolysates of all 4 contained hexosamine (glucosamine), rhamnose and glucose. A polysaccharide extracted from 2 serological types by either alkaline treatment or mechanical disruption was serologically group-specific. Acid hydrolysates contained glucose and no other single component in comparable amount. The group-specific polysaccharide, which may be of a dextran-like nature, is probably situated wholly or in part at the surface of the streptococcus.

Cell Wall↗
PubMed1951

An electrophoretic study of a streptococcal proteinase and its precursor.

An electrophoretic study of crystalline preparations of a streptococcal proteinase and its precursor established their isoelectric points at pH values of 8.42 and 7.35 respectively (ionic strength 0.10). Preparations of the proteinase appeared to be electrophoretically homogeneous over a pH range of 5 to 8.5. Precursor preparations contained a relatively low concentration of the active enzyme visible as a separate peak in electrophoretic patterns of sufficiently concentrated solutions. Autocatalytic conversion of precursor to active enzyme was complete and resulted in a corresponding change in the electrophoretic pattern. Treatment of precursor preparations with trypsin produced incomplete conversion to the active enzyme and resulted in the formation of a modified precursor protein. This differed from the parent substance in electrophoretic mobility and in susceptibility to trypsin, but resembled it in immunological specificity and, as previously shown, in susceptibility to conversion to active enzyme by autocatalysis. Serological reactions of precursor and active enzyme components withdrawn from the cell after electrophoresis are described. It appears that the precursor protein may have two antigenic groups, one specific, the other shared by the active enzyme which behaves as a single antigen.

Cysteine Endopeptidases↗
PubMed1950

The crystallization and serological differentiation of a streptococcal proteinase and its precursor.

Grown in dialysate broth at a pH between 5.5 and 6.5, some strains of group A streptococci elaborate the precursor of a proteolytic enzyme. Within this range of hydrogen concentration the precursor is also produced when the streptococci are suspended in a peptone dialysate containing glucose and incubated at 37 degrees C. The precursor does not appear to be produced at a neutral or alkaline reaction. Methods are described whereby the precursor and proteinase have been isolated in crystalline form. The precursor crystallizes from half-saturated ammonium sulfate at pH 8.0 and a temperature of 22 degrees C. or higher; the proteinase crystallizes from 0.15 saturated ammonium sulfate at pH 8.0 but does so most readily at refrigerator temperature. The degree of purification achieved by these procedures is discussed. The activity of purified preparations of the precursor and of proteinase has been tested against alpha-benzoyl-l-arginineamide and, with this as a substrate, the conversion of precursor to proteinase by autocatalysis or by trypsin has been confirmed. Immunological experiments are described, the results of which provide evidence of the distinct antigenic specificity of the precursor and proteinase; the conversion of precursor to proteinase has been followed by means of serological tests.

Crystallization↗