Purification from human plasma of a tetrapeptide that potentiates insulin‐like growth factor‐I activity in chick embryo cartilage

Abstract
Human plasma has been shown to contain a low molecular weight factor that potentiates human IGF‐I stimulation of glycosaminoglycan synthesis in chick embryo cartilage. The peptide was purified and characterized by Edman degradation and electrospray mass spectrometry. The primary structure determined was: Trp‐Gly‐His‐Glu. A homologous synthetic peptide similarly promoted matrix biosynthesis in cartilage exposed to IGF‐1.