Nitrogenous constituents of the thoracic muscle of the African migratory locust (Locusta migratoria migratorioides)

Abstract

Total non-protein N values of trichloroacetic acid extracts of locust muscle varied from 290 to 400 mg/100 g of muscle and rose with the increasing age of the locusts. About 80% of the total non-protein N was accounted for as amino acid N, purines and volatile amines, a-Amino N values of trichloroacetic acid extracts of muscle varied from 60 to 190 mg/100 g of fresh muscle. The values were low in the extracts made from the muscle of locusts shortly after emergence from the final moult, but rose to a peak before the onset of mating. In trichloroacetic acid extracts of muscle the amount of taurine increased with the increasing age of the locusts. Glutamine was abundant before egg-laying and fell to 1/10 of its original value after this time. Glutamic acid, alanine, valine, leucine (including isoleucine) and an unidentified ninhydrin-staining substance all fell to about 1/3 of their original amounts at the time of egg-laying, whereas arginine and glycine rose slightly. Uric acid accounted for 8 mg of N/100 g of muscle in newly moulted adult locusts. The value fell to 1-5 mg 6 days later, and some could be detected after 14 days. Adenylic acid accounted for 20 to 60 mg of N/100 g of fresh muscle, and was presumably present as adenosine triphosphate in the intact muscle. Seventeen amino acids were detected in acid hydrolyzates of locust-muscle protein, including the unusual amino acid lanthionine.