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HeLp, a heme-transporting lipoprotein with an antioxidant role
Clarissa M Maya-Monteiro1, Liliane R Alves, Nelson Pinhal
1Departamento de Bioquímica Médica, ICB, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-590, Brazil. clarissa@ioc.fiocruz.br
Insect Biochemistry and Molecular Biology
|February 24, 2004
Summary
The Boophilus microplus heme-binding lipoprotein (HeLp) acts as an antioxidant, protecting against heme-induced lipid damage. This unique lipoprotein prevents cell damage while preserving heme for the tick
Area of Science:
- Biochemistry
- Parasitology
- Lipid Metabolism
Background:
- Plasma lipoproteins are crucial for lipid transport but can be targets of free radical damage.
- The tick Boophilus microplus possesses a unique heme-binding lipoprotein (HeLp) for transporting dietary heme.
Purpose of the Study:
- To investigate the antioxidant properties of the Boophilus microplus heme-binding lipoprotein (HeLp).
- To determine if HeLp can protect against heme-induced oxidative damage.
Main Methods:
- Lipid peroxidation assays using phospholipid liposomes and heme.
- Red blood cell lysis assays in the presence of heme.
- Assays examining reactions of heme with tert-butyl hydroperoxide and hydrogen peroxide.
Main Results:
- HeLp addition inhibited heme-induced lipid peroxidation in liposomes.
- HeLp prevented heme-mediated lysis of red blood cells.
- HeLp demonstrated antioxidant activity against heme's reactions with peroxides.
Conclusions:
- The heme-binding lipoprotein (HeLp) of Boophilus microplus possesses intrinsic antioxidant capabilities.
- HeLp protects against heme toxicity through a novel mechanism, preserving heme for tick reuse.