The chemistry of insect haemolymph—IV. Acid-soluble phosphates

Abstract

The acid-soluble phosphate compounds in the haemolymph plasma of several lepidopterous insects have been fractionated quantitatively by ion-exchange chromatography, and the principal components identified. In Hyalophora cecropia, total acid-soluble P ranged from 26 to 44 mM, and the main components were inorganic orthophosphate, α-glycerophosphate, phosphorylcholine, and phosphorylethanolamine. Present in smaller amounts were uridine diphosphate n-acetylgalactosamine and some other uridine diphosphate derivatives. The presence of a phosphagen was also indicated. Quantitatively, orthophosphate and the basic phosphates tended to be more abundant during diapause than in the active stages, while glycerophosphate changed in the reverse manner. Injected orthophosphate- 32P was incorporated into the various esters at all stages, though at reduced rates during diapause; but when cell-free haemolymph was incubated with 32P, incorporation was negligible. In Antheraea polyphemus, Samia cynthia, and Protoparce sexta, the distribution of phosphates was similar to that in H. cecropia. In Bombyx mori, however, there was little α-glycerophosphate whereas sorbitol-6-phosphate was abundant and glucose-6-phosphate was also found.