Rat epidermal growth factor: complete amino acid sequence: Homology with the correspondence murine and human proteins; isolation of a form truncated at both ends with full in vitro biological activity

Abstract

Epidermal growth factor (EGF) isolated from the submaxillary gland of the rat (rEGF) is missing the COOH‐terminal five residues present in both mouse and human EGF. rEGF competes for the binding of 125I‐labelled mEGF to human carcinoma cells with the same affinity as mEGF. rEGF and mEGF have identical mitogenic activities on mouse 3T3 fibroblasts, thus the C‐terminal region of the sequence is not necessary for the in vitro activity of EGF. Using reversed‐phase high‐performance liquid chromatography, four molecular forms of EGF have been extracted from rat submaxillary glands. These forms represent rEGF, rEGF(2–48), rEGF(3–48) and rEGF(4–48); all forms appear to be equipotent in both the rece..