Isolation and characterization of the subunits of bovine follitropin.
Highly purified bovine follitropin was dissociated into its alpha- and beta-subunits after treatment with 1 M-propionic acid. The dissociated subunits were fractionated by chromatography on DEAE-cellulose and further purified by gel filtration on Sephadex G-100. The isolated alpha- and beta-subunits were biologically inactive, but their recombinants regenerated 80% of the follitropin activity. The alpha-subunit of bovine follitropin recombined with the beta-subunits of bovine lutropin and thyrotropin to regenerate 70% of lutropin and 50% of thyrotropin activities respectively. The beta-subunit of bovine follitropin recombined with the alpha-subunit of either bovine lutropin or thyrotropin to regenerate about 75% of follitropin activity. Recombinations were monitored by specific radioligand-receptor assays and polyacrylamide-gel electrophoresis. The elution volumes of the alpha- and beta-subunits of bovine follitropin after gel filtration on Sephadex G-100 were almost identical. The amino acid composition of bovine follitropin-alpha was low in histidine, arginine, isoleucine and leucine, but relatively high in lysine, threonine and glutamic acid. The bovine follitropin-beta contained one methionine residue and low amounts of histidine and phenylalanine, but relatively high in aspartic acid, threonine and glutamic acid. The N-terminal residues of the alpha- and beta-subunits of bovine follitropin were identified to be phenylalanine and glycine respectively.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D005640:Follicle Stimulating Hormone / Q000302:isolation & purification*; D007986:Luteinizing Hormone; D013972:Thyrotropin
D000596:Amino Acids; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013972:Thyrotropin