INCREASE OF ANTI-ULCEROGENIC ACTIVITY BY REDUCTION AND ALKYLATION OF DISULFIDE BONDS OF A GLOBULIN FRACTION FROM BOVINE SERUM

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Bovine serum was subjected to ammonium sulfate fractionation, and subsequently chromatographed on DEAE-cellulose column to obtain a globulin protein having a weak auti-ulcerogenic activity, Fr. II-A. Agar immunoelectrophoresis and immunodiffusion using rabbit antiserum against bovine IgG revealed that Fr. II-A from bovine serum shared antigenic determinant with bovine IgG. Furthermore, Fr. II-A showed a single band on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. By reducing and alkylating the disulfide bonds by 2-mercaptoethanol and iodoacetic acid, Fr. II-A was separated into two subfragments in the same manner as in the case of immunoglobulin to produce Fr. L (molecular weight ; 24000) and Fr. H (molecular weight ; 50000). Fr. L showed anti-ulcerogenic activity up to about ten times greater than that of original Fr. II-A, but in the case of Fr. H, the activity increased approximately several times. Fr. L showed significant activity in preventing ulcer formation and gastric juice secretion in pylorus-ligated rats, and was also effective in reducing index of the phenylbutazoneinduced ulcer.