Isolation and Characterization of Bovine Thyrocalcitonin

Bovine thyrocalcitonin has been isolated in homogeneous form following a 40,000-fold purification.The isolated hormone contains 32 amino acids including Argl, Hisr, Thrz, Ser4, GluI, ProB, Glys, Alan Vain MetI, Asm, AspI, Lysl, Tyrz, Phez, Leus, TrpI, Cysp.The purified peptide is resolved by chromatography on cellulose thin layer plates or carboxymethyl cellulose into two components.These two components diEer in the oxidative state of the methionine residue; however, both forms have an equal biological activity of 200 Medical Research Council units per mg.The amino acid composition of the bovine hormone differs from the porcine by 3 residues, the human by 18, and the salmon by 16.