ABSTRACT
Half-cystine peptides were isolated from the enzymatic digest of reduced and carbamidomethylated alpaca growth hormone. From their amino acid composition and determination of the end terminal residues we propose the amino acid sequence around the two disulphide bridges, partially based on homology with other mammalian growth hormones. The proposed sequence is identical to that of equine growth hormone and very similar to those of rat, bovine and ovine hormones.
Subject(s)
Cystine/analysis , Growth Hormone/analysis , Amino Acid Sequence , Animals , Camelids, New World , Chemical Fractionation , Cystine/isolation & purification , Electrophoresis, Polyacrylamide GelABSTRACT
Half-cystine peptides were isolated from the enzymatic digest of reduced and carbamidomethylated alpaca growth hormone. From their amino acid composition and determination of the end terminal residues we propose the amino acid sequence around the two disulphide bridges, partially based on homology with other mammalian growth hormones. The proposed sequence is identical to that of equine growth hormone and very similar to those of rat, bovine and ovine hormones.
ABSTRACT
A simple and mild procedure is described for the isolation of pituitary growth hormone from alpaca glands. It involves extractions in buffer at pH 8.7 and gel filtration in Sephadex G-75. an average yield of 1 mg purified product may be obtained from 1 g fresh alpaca pituitary glands. The alpaca hormone was examined for homogeneity by SDS-polyacrylamide gel electrophoresis, gel electro-focusing and end-group analyses. It is a protein composed of a single polypeptide chain with phenylalanine at both ends. The C-terminal sequence is -Ala-Phe. The molecular weight is approximately 21 700 and the amino acid composition very similar to that observed in equine growth hormone.
