Isolation of an acidic protein from rat brain.

In aqueous extracts of rat brain, spinal cord, and sciatic nerve, a protein antigen has been detected which could not be shown in similarly prepared extracts of a variety of other rat tissues. The protein, designated antigen (Y, had a high mobility in zone electrophoresis at pH 7.4. Antigen cr was isolated and was found to consist of a single type of subunit having a molecular weight of about 39,000. Evidence was obtained to suggest that the protein occurs in various aggregates stabilized by disulfide bonds. Antigen 01 is immunologically unrelated to another recently isolated acidic brain protein, the S-100 protein.