Primary structure of two low molecular weight proteins isolated from cuticle of fifth instar nymphs of the migratory locust, Locusta migratoria

The cuticle from mid-instar fifth stage locust (Locusta migratoria) contains close to a hundred extractable proteins, which can be separated by means of two-dimensional polyacrylamide gel-electrophoresis. A few of the proteins have been purified by ion-exchange chromatography, and the complete amino acid sequence has been determined for two of them. They are probably of endocuticular origin. Both proteins are small (33 and 88 amino acid residues, respectively), and none of them are secondarily modified. The sequence of the smallest protein shows pronounced similarity to local sequences found in proteins from pharate adult cuticle of the same species, whereas the other protein shows no similarities to cuticular proteins obtained from this or from other insect species.