SOLID PHASE SYNTHESIS OF BOVINE PITUITARY GROWTH HORMONE‐(123–131) NONAPEPTIDE

Abstract
A nonapeptide, Arg‐Glu‐Leu‐Glu‐Asp‐Gly‐Thr‐Pro‐Arg, corresponding to the 123–131 sequence of bovine pituitary growth hormone, was prepared by a modified solid phase synthesis. To avoid an acid‐ or base‐catalysed rearrangement at the Asp‐Gly bond, which gives rise to an aspartimide‐containing peptide, a new combination of protecting groups was introduced. The 2‐(4‐biphenylyl)‐2‐propyloxycarbonyl group was used for Nα‐protection, a t‐butyl ester for the β‐carboxyl of aspartic acid, and a p‐alkoxybenzyl alcohol ester for the anchoring bond to the resin support. The nonapeptide showed growth hormone activity in the hypophysectomized rat tibia epiphyseal width test, but was inactive in the hypophysectomized rat body weight gain test.