Alpha-1-acute phase globulin in the blood of tunicamycin-injected rats. Isolation of the non-glycosylated form, its inhibitory properties and synthesis in liver slices.

Plasma of rats injected with tunicamycin (2 micrograms/g body wt) shows on crossed immunoelectrophoresis the presence of an additional, slowly migrating component of alpha 1-acute-phase globulin (alpha 1-AP-globulin). The native and modified forms of alpha 1-AP-globulin were jointly isolated on the column of immobilized antibodies and then separated by chromatofocusing on polybuffer exchanger. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate demonstrated that tunicamycin-induced form of rat alpha 1-AP-globulin has Mr of 50,000 and is devoid of carbohydrates as inferred from the lack of staining with Schiff reagent. However, during incubation with papain in vitro it is only slightly less effective than mature glycosylated alpha 1-AP-globulin (Mr 68 000) in inhibiting hydrolysis of CBZ-Lys-ONp. Incubation of liver slices from control and tunicamycin-injected rats with 14C-leucine demonstrated that tunicamycin reduces synthesis and release to the medium of alpha 1-AP-globulin and some other plasma proteins, but the proportion of aglyco-alpha 1-AP-globulin is higher than in plasma.