Investigation of a persistently raised serum AST.

The AST responsible for a raised enzyme activity, with otherwise normal biochemistry, in a single individual over a 16-month period has been characterized as an IgG (lambda)-AST complex by (i) estimation of the molecular size by gel exclusion chromatography on Sephadex G200, (ii) agarose gel electrophoresis, (iii) immunoprecipitation by anti-immunoglobulin antisera and (iv) adsorption on to protein A-agarose.