Premium
A high molecular weight diapause‐associated protein from the stem‐borer Busseola fusca : Purification and properties
Author(s) -
Osir Ellie O.,
Labongo Lanek V.,
Unnithan Gopalan C.
Publication year - 1989
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.940110305
Subject(s) - biology , hemolymph , biochemistry , diapause , storage protein , methionine , lepidoptera genitalia , molecular mass , amino acid , botany , larva , gene , enzyme
The hemolymph of diapausing larvae of the stem borer, Busseola fusca Fuller (Lepidoptera: Noctuidae), contains an electrophoretically distinct protein band on nondenaturing polyacrylamide gels. The protein, called the Busseola diapause protein (BDP), was purified by a combination of density gradient ultracentrifugation, gel permeation, and affinity chromatography. It is a high molecular weight protein (M r ∼5 × 10 5 ; pl = 6.1) that is composed of two subunits, I (M r ∼88,000 ± 4,000) and II (M r ∼79,000 ± 1,000), which are not linked by disulfide bridges. The protein contains both lipids (2%) as well as covalently bound carbohydrates (1%). The inability to stain the fluorescein isothiocyanate‐conjugated concanavalin A (FITC‐Con A) suggests that the carbohydrate moiety of BDP is not of the high mannose type. Amino acid analysis showed a high tyrosine plus phenylalanine content (16 mol%). Labeling studies using [ 35 S]‐methionine showed that de novo synthesis by the fat body tissue occurs only in diapausing larval insects. It is proposed that the BDP could serve a storage function by providing the amino acids needed for the synthesis of pupal and adult structures.