Structure-activity relationships of human epidermal growth factor(h-EGF).
The 53 amino acid regulatory peptide, human epidermal growth factor (h-EGF), is a potent mitogen that stimulates cellular proliferation and differentiation in a wide variety of cells. To identify the critical residues that elicit the biological activity of h-EGF, peptides were constructed by stepwise solid-phase synthesis using the Boc-HF strategy. These synthetic peptides were characterized by HPLC, FAB-MS, amino acid analysis and thermolytic digestion. The mitogenic activity of these h-EGF analogues was determined by the stimulation of [3H]-thymidine uptake into DNA in NIH-3T3 fibroblast cell lines. Substituting Tyr with Phe at position's 37 and 13 had little effect on the mitogenic activity of h-EGF. In contrast, Ala at these positions resulted in a severe loss of activity (20 and 10(3)-fold). These results indicate that the hydrophobicity of the side chain at positions 13 and 37 of h-EGF is essential for its biological activity. A semiconservative substitution of Leu with Ala at position 15 and a conservative change of Lys at position 41 also drastically reduced mitogenic activity (10(4) and 10(5)-fold). Thus, the bulky hydrophobic side chain at position 15 and the guanidino group at position 41 are indispensable in determining the biological activity of h-EGF.
Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan.
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Shin
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Watanabe
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Kako
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Ohtaki
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Munekata
D016475:3T3 Cells / Q000187:drug effects / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D004815:Epidermal Growth Factor / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D005563:Formic Acid Esters / Q000737:chemistry; D051379:Mice; D008969:Molecular Sequence Data; D013329:Structure-Activity Relationship; D013936:Thymidine / Q000493:pharmacokinetics; D014316:Tritium
D005563:Formic Acid Esters; C000345:t-butyloxycarbonyl group; D014316:Tritium; D004815:Epidermal Growth Factor; D013936:Thymidine