Amino acids in the haemolymph of Popillia japonica (Newman) larvae

Abstract The proteins were separated from the acid-soluble components in haemolymph of Popillia japonica (Newman) larvae with 5% trichloroacetic acid, and the resulting materials analysed for amino acid content. Altogether twenty amino acids were identified in whole or hydrolysed haemolymph or in fractions. Analysis was done by paper chromatography and ion exchange chromatography. Glutamine, arginine, histidine, proline, glycine, alanine, and valine occur free in considerable amounts in the haemolymph. Lysine, aspartic acid, threonine, serine, glutamic acid, isoleucine, leucine, tyrosine, β -alanine, tryptophan, and asparagine were also detected. Sixteen amino acids were identified in the insoluble proteinaceous material. Phenylalanine and methionine were present in the insoluble fraction, but not to an appreciable extent in any other fractions. There were several peptides that disappeared on acid hydrolysis. There were at least two unidentified ninhydrinreacting substances that were stable to acid.