title: A heme-binding protein from hemolymph and oocytes of the blood-sucking insect, Rhodnius prolixus. Isolation and characterization.
abstract: A heme-binding protein has been isolated and characterized from both the hemolymph and oocytes of the blood-sucking insect, Rhodnius prolixus. The protein from both sources is identical in most aspects studied. The Rhodnius heme-binding protein (RHBP) is composed of a single 15-kDa polypeptide chain coiled in a highly alpha-helical structure which binds non-covalently one heme/polypeptide chain. This RHBP is not produced by limited degradation of hemoglobin from the vertebrate host, since specific polyclonal antibodies against it do not cross-react with rabbit hemoglobin, and since it differs from hemoglobin in having a distinct amino-acid composition and NH2-terminal sequence. The spectrum of the dithionite-reduced protein has peaks at 426, 530, and 559 nm and resembles that of a b-type cytochrome. RHBP from hemolymph is not saturated with heme and promptly binds heme added to the solution. The oocyte protein, on the other hand, is fully saturated and is not capable of binding additional heme.
authors.affiliation: Departamento de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Brasil.
authors.forename: P L
authors.initials: PL
authors.lastname: Oliveira
authors.forename: J K
authors.initials: JK
authors.lastname: Kawooya
authors.forename: J M
authors.initials: JM
authors.lastname: Ribeiro
authors.forename: T
authors.initials: T
authors.lastname: Meyer
authors.forename: R
authors.initials: R
authors.lastname: Poorman
authors.forename: E W
authors.initials: EW
authors.lastname: Alves
authors.forename: F A
authors.initials: FA
authors.lastname: Walker
authors.forename: E A
authors.initials: EA
authors.lastname: Machado
authors.forename: R H
authors.initials: RH
authors.lastname: Nussenzveig
authors.forename: G J
authors.initials: GJ
authors.lastname: Padovan
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000737:chemistry / Q000302:isolation & purification*; D005260:Female; D006418:Heme / Q000378:metabolism; D000081062:Heme-Binding Proteins; D006420:Hemeproteins / Q000737:chemistry / Q000302:isolation & purification*; D006458:Hemolymph / Q000737:chemistry*; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009865:Oocytes / Q000737:chemistry; D012239:Rhodnius / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D000596:Amino Acids; D002352:Carrier Proteins; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; D006418:Heme