Studies on the protein metabolism of Culex pipiens L.—IV. Separation of free amino acids and peptides in adult mosquitoes by column chromatography

Abstract

Separation of free amino acids and peptides in methanol extracts of adult mosquitoes ( Culex pipiens and C. fatigans) was accomplished with Dowex-50 column chromatography in a gradient elution system. In addition to the amino acids previously reported, tryptophan and phenylalanine were detected and leucine and isoleucine could be separated distinctly. The relative concentrations of the various amino acids are in good agreement with those previously estimated by paper chromatography. Furthermore, the detailed analyses revealed the presence of at least thirty different peptides and amino acid derivatives, which amount to about 14–19 per cent of the total ninhydrin-positive components. Some preliminary data on the amino acid compositions of these compounds are given. The present results do not suggest any unusual features, at least not at the level of free amino acids and peptides, which could be responsible for the initiation of ovarian development in autogenous mosquitoes.