Pituitary lactogenic hormone. XXXVII. Synthesis and properties of the carboxyl terminal cyclic undecapeptide.

The carboxyl terminal cyclic undecapeptide of the ovine prolactin molecule: Leu-Asn-Cys-Arg-Ile-Ile-Tyr-Asn-Asn-Asn-Cys has been synthesized by the solid-phase method. The circular dichroism of the synthetic peptide has been investigated. It was also found that the cyclic undecapeptide does not have pigeon crop-sac stimulating activity, or immunological activity when tested by complement fixation experiments.