title: Antioxidant role of Rhodnius prolixus heme-binding protein. Protection against heme-induced lipid peroxidation.
abstract: Heme in aqueous solutions actively promotes free radical reactions leading to degradation of biological molecules. The blood-sucking insect Rhodnius prolixus has a heme-binding protein (RHBP) in its hemolymph (Oliveira, P.L., Kawooya, J.K., Ribeiro, J.M.C., Meyer, T., Poorman, R., Alves, E.W., Walker, F., Padovan, G.J., and Masuda, H. (1994) J. Biol. Chem. 270, 10897-10901. Here we show that this protein inhibits heme-dependent peroxidation of both linolenic acid liposomes and lipophorin, the main lipoprotein of insect hemolymph. The oxidized lipophorin is functionally impaired, being defective both in its capacity to be loaded with phospholipids from the fat body as well as in its ability to deliver phospholipids to the growing oocytes. RHBP prevents the heme-induced oxidative damage to lipophorin. It is proposed that in vivo RHBP binds the heme derived from digestion of blood hemoglobin, suppressing the generation of activated oxygen species and protecting the insect against oxidative stress throughout the feeding cycle.
authors.affiliation: Departamento de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Brasil.
authors.forename: M
authors.initials: M
authors.lastname: Dansa-Petretski
authors.forename: J M
authors.initials: JM
authors.lastname: Ribeiro
authors.forename: G C
authors.initials: GC
authors.lastname: Atella
authors.forename: H
authors.initials: H
authors.lastname: Masuda
authors.forename: P L
authors.initials: PL
authors.lastname: Oliveira
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D000975:Antioxidants; D002352:Carrier Proteins / Q000378:metabolism*; D005260:Female; D000081062:Heme-Binding Proteins; D006420:Hemeproteins / Q000378:metabolism*; D006458:Hemolymph / Q000737:chemistry; D008054:Lipid Peroxides / Q000378:metabolism*; D008074:Lipoproteins; D010053:Ovary / Q000378:metabolism; D010084:Oxidation-Reduction; D010743:Phospholipids / Q000378:metabolism; D012239:Rhodnius / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000975:Antioxidants; D002352:Carrier Proteins; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; D008054:Lipid Peroxides; D008074:Lipoproteins; D010743:Phospholipids; C032830:lipophorin