Isolation of the Hypertrehalosaemic Factors I and II from the Corpus cardiacum of the Indian Stick Insect,Carausius morosus,by Reversed-Phase High-Performance Liquid Chromatography, and Amino-Acid Composition of Factor II

Abstract

The separation of 2 peptides with hypertrehalosemic activity from the corpus cardiacum of the Indian stick insect, C. morosus, was achieved by reversed-phase high performance liquid chromatography using a Nucleosil C-18 column with a trifluoroacetic acid/acetonitrile gradient. The eluant was monitored at 210 nm and the hypertrehalosemic activity was detected in ligated stick insects using a bioassay. In addition, the isolated material was potent in causing hyperlipemia in migratory locusts and also in raising blood carbohydrates in the American cockroach. The amino-acid composition of the major peptide, hypertrehalosemic factor II , was determined after acid hydrolysis with HCl or methanesulfonic acid. Apparently, factor II is a nonapeptide which contains the following amino-acid residues: Asp, 2 Thr, Glu, Pro, Gly, Leu, Phe and Trp. This composition is almost identical to that of locust adipokinetic hormone I, lacking only 1 Asp residue.