Relationships of Thyrotropin to Exophthalmic-producing Substance: PURIFICATION OF HOMOGENEOUS GLYCOPROTEINS CONTAINING BOTH ACTIVITIES FROM [3H]-LABELED PITUITARY EXTRACTS

摘要: Abstract Preparations of thyrotropin which are purified by standard procedures column chromatography contain several electrophoretically distinct components have exophthalmogenic activity and galactose. Although preparative disc gel electrophoresis can resolve these heterogeneous preparations into individual glycoproteins, the resultant still both thyrotropic activity. Two such each with activities, homogeneous in ultracentrifuge, a molecular weight 27,000 ± 3,000. They similar, if not identical, amino acid composition. Previous suggestions that determinants for reside on same glycoprotein molecule reinforced data. Terminal galactose residues glycoproteins may be enzymatically labeled tritium. This procedure involves preliminary exposure to oxidase subsequent reduction (3H) sodium borohydride. Application this technique has established terminal nature multiactive but obtained electrophoresis. Both activities preserved tritiated glycoproteins. The is applicable crude pituitary preparations, tritium serving as convenient marker species once contaminant been removed. Thyroid-stimulating hormone derived from mouse transplantable tumors also contains tritiation. Distinct differences bovine otherwise shown its sugar