Drosophila hemolymph proteins: purification, characterization, and genetic mapping of larval serum protein 2 in D. melanogaster.

Three of the major protein species present in the hemolymph of Drosophila melanogaster larvae just prior to pupation are absent from second instar larvae but accumulate rapidly during the third instar. This article describes the purification and characterization of one of these, larval serum protein (LSP) 2, using an immunological assay. It is a homohexamer of molecular weight about 450,000, with a polypeptide molecular weight of 78,000--83,000. Fast and slow electrophoretic variants of this protein map between the markers vin and gs, at 36--37 on chromosome 3.