pubmed:abstractText |
The immobilization antigen (i-antigen) fraction of Paramecium aurelia syngen 4 is shown to contain a protease that is activated by mercaptoethaneol. After the protease has been heat-inactivated, the molecular weight of the i-antigen (similar to 250,000 daltons) cannot be decreased by mercaptoethanol treatment. It is demonstrated that the i-antigen is a single polypeptide chain. Reasons are also given why low molecular weight subunits were previously reported by other authors.
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