Purification of rabbit sperm autoantigens by preparative SDS gel electrophoresis: amino acid and carbohydrate content of RSA-1.

This study has described a relatively simple preparative procedure for isolating sperm autoantigens from testis membrane pellets using an SDS-7%-15% polyacrylamide gradient prep-disc gel column. Using this system, the rabbit sperm membrane autoantigen, RSA-1, has been isolated without the use of an immunoadsorbent column, giving an almost 10-fold greater yield than with the immunoadsorbent column method. A second autoantigen (RSA-2) has also been isolated. Both RSA-1 and RSA-2 retain their antigenic activity after isolation from the prep-disc gel. The carbohydrate and amino acid content of RSA-1 was determined. RSA-1 is 9.1% carbohydrate and by gas liquid chromatographic analysis contains xylose, galactose, mannose, glucose and glucosamine. The average hydrophobicity of RSA-1 indicates that it is a relatively nonpolar, asymmetric protein in the general category of fibrous or tropomyosin-like proteins.