A polypeptide antigen from a strain of Staphylococcus simulans. 1. Purification and some chemical data

A polypeptide antigen isolated from Staphylococcus simulans was shown mainly to contain alanine and aspartic acid in a molar ratio of 3:1. The circular dichroism spectre showed only positive ellipticities, and oxidation by D-amino acid oxidase showed the presence of D-alanine. 65 per cent of the alanine was present as the D-isomer as estimated by gas-liquid chromatography. Analytical ultracentrifugation showed that the polymer sedimented as a homogeneous peak with an S20, W value of 2.8.