Amino acid sequence of progesterone-induced rabbit uteroglobin

Uteroglobin, a steroid-binding protein of the uterine secretion of the rabbit which is induced by progesterone, comprises two identical polypeptide chains of 70 amino acid residues linked by two disulfide bonds. The primary structure has been determined by using both automated and manual methods of Edman degradation. Overlapping peptides were isolated from tryptic, and CNBr digests. The sequence is not homologous to any known protein except for a small acidic region (residues 22-29) resembling a sequence found in somatotropin. The C-terminal half is relatively basic. Implications for the secondary structure are discussed.