Amino acid sequence of progesterone-induced rabbit uteroglobin

Abstract

Uteroglobin, a steroid-binding protein of the uterine secretion of the rabbit which is induced by progesterone, comprises 2 identical polypeptide chains of 70 amino acid residues linked by 2 disulfide bonds. The primary structure was determined by using automated and manual methods of Edman degradation. Overlapping peptides were isolated from tryptic, chymotryptic and CNBr digests. The sequence was 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 was relatively basic. Implications for the secondary structure are discussed.