title: Could cholesterol bound to haemoglobin be a missing link for the occasional inverse relationship between superoxide dismutase and glutathione peroxidase activities?
abstract: The concept of an anti-oxidant defence system as a means to prevent oxidative cell damage implies balanced activities of anti-oxidant defence enzymes. As well as positive correlations between anti-oxidant enzyme activities in human erythrocytes, it has been observed that sometimes when glutathione peroxidase activity is increased, CuZn-superoxide dismutase activity is decreased. In our current study we have examined the plasma lipid profile and the anti-oxidant defence enzymes in erythrocytes from humans, pigs, and bulls. We found that a negative correlation existed between CuZn-superoxide dismutase and glutathione peroxidase activities in human erythrocytes when the concentrations of both plasma triglycerides and total cholesterol were high. This correlation was also found in pig erythrocytes, but not in bull erythrocytes. We propose that cholesterol could affect membrane lipid peroxidation and superoxide generation in erythrocytes via the recently found fraction of cholesterol bound to haemoglobin, termed haemoglobin-cholesterol.
authors.affiliation: Department of Chemistry, University of Belgrade, Studentski trg 16, 11001 Belgrade, Serbia and Montenegro.
authors.forename: Milan
authors.initials: M
authors.lastname: Nikolic
authors.forename: Danijela
authors.initials: D
authors.lastname: Vranic
authors.forename: Aurelija
authors.initials: A
authors.lastname: Spiric
authors.forename: Valentina
authors.initials: V
authors.lastname: Batas
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Nikolic-Kokic
authors.forename: Petar
authors.initials: P
authors.lastname: Radetic
authors.forename: Lazar
authors.initials: L
authors.lastname: Turubatovic
authors.forename: Dusko P
authors.initials: DP
authors.lastname: Blagojevic
authors.forename: David R
authors.initials: DR
authors.lastname: Jones
authors.forename: Vesna
authors.initials: V
authors.lastname: Niketic
authors.forename: Mihajlo B
authors.initials: MB
authors.lastname: Spasic
mesh_terms: D000818:Animals; D002417:Cattle; D002784:Cholesterol / Q000378:metabolism*; D004789:Enzyme Activation; D004912:Erythrocytes / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism*; D006454:Hemoglobins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D015227:Lipid Peroxidation; D008563:Membrane Lipids / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism*; D013552:Swine
chemical_list: D006454:Hemoglobins; D008563:Membrane Lipids; D002784:Cholesterol; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase