The Fate of Tritiated rm-Epidermal Growth Factor in the Sheep: Validation of the Labelling Procedure and Rate of Tissue Clearance

Abstract

Plasmid-derived recombinant mouse epidermal growth factor, rm-EGF, was purified by ion pair reversed phase high performance liquid chromatography. The product peak (termed rm-a-EGF) was characterized by physicochemical techniques including fast atom bombardment mass spectrometry, high field proton magnetic resonance and amino acid sequencing (amino acid arrangement and composition). The rm-a-EGF was tritiated, labile tritium removed by lyophilization: and the product purified and characterized as for the parent compound to yield a compound identical to rm-a-EGF except for the isotopic hydrogen substitution. Label stability was validated by lyophilization of samples, especially urine.