A high molecular weight diapause‐associated protein from the stem‐borer Busseola fusca: Purification and properties

Publication Type

Journal Article

Journal Name

Archives of Insect Biochemistry and Physiology

Publication Date

1-1-1989

Abstract

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 (Mr ∼5 × 105; pl = 6.1) that is composed of two subunits, I (Mr ∼88,000 ± 4,000) and II (Mr ∼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 [35S]‐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. Copyright © 1989 Wiley‐Liss, Inc.

Keywords

Busseola‐diapause protein, immunology, physical‐chemical properties

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