| Abstract: | Purified, intact orosomucoid (alpha 1-acid glycoprotein) derived from whole human plasma was incubated with a number of proteolytic and saccharolytic enzymes under a variety of conditions. The unfractionated digests were immediately examined by both agar gel- and immunoelectrophoresis for the presence of antigenically active (precipitating) and/or inactive macrofragments. Despite otherwise clear evidence of rapid degradation by several proteases, no antigenic subunits were detected. Among the glycosidases, almond emulsin produced a suggestion of modification of the carbohydrate moiety of a sialic acid-poor orosomucoid preparation obtained from Cohn Fr. VI, but had no effect on antigenic properties. These results are presented as further evidence for a lack of involvement of the extensive carbohydrate component of orosomucoid in its antigenic reactions, and support previous data implicating the polypeptide chain as solely responsible for its antigenicity. |
