COMPARISON OF LARVAL AND PUPAL CUTICULAR PROTEINS IN TENEBRIO-MOLITOR

Protein extracts from pupal and larval pharate cuticle from the meal w orm, Tenebrio molitor, gave nearly identical patterns by two-dimension al electrophoresis and by ion-exchange chromatography. The main compon ents in the cuticular extracts from the two metamorphic stages were al so identical with respect to molecular mass according to electrospray ionization mass spectrometry. The complete amino acid sequence for one of the pupal cuticular proteins was determined; according to partial amino acid sequences and the mass spectrometric peptide map for the co rresponding larval cuticular protein, it was concluded that the larval protein has the same amino acid sequence as the pupal protein. The se quence is characterized by a high content of alanine, proline, valine, and tyrosine and the complete absence of acidic amino acid residues, the sulphur containing amino acids and tryptophan. The sequence is fur ther characterized by a high frequency of repeated sequence motifs, am ong which the Ala-Ala-Pro-Ala motif is the most abundant, but also lon ger sequence motifs are repeated. The sequence shows striking resembla nce to sequences of proteins isolated from pharate locust cuticle.