Immunological behavior of two alloforms of ATPase fromMicrococcus lysodeikticus.

Antisera were raised in rabbits to two alloforms of ATPase isolated from two substrains ofMicrococcus lysodeikticus. These alloforms show a similar amino acid composition but differ in the associated carbohydrate components. Similarities and differences in the immunological behavior of the two forms have been assessed by immunodiffusion, immunoelectrophoresis, and crossed immunoelectrophoresis. The ATPase forms show a great extent of homology as might be expected from their relatedness in amino acid composition. Differences in immunological properties are also evident. They do not seem primarily to reflect the differences in the glycan constituents, but do result from the polymorphism of the purified ATPase molecule of each form. This heterogeneity (microheterogeneity) is a consequence of the lability of the ATPase molecule and influences its behavior as antigen and immunogen.