Differential prooxidative effect of adult and fetal hemoglobin

Abstract

Human fetal hemoglobin assayed in a peroxidizing system shows an increased prooxidative effect when compared to human adult hemoglobin. This effect is related only to the oxyhemoglobin form since both fetal and adult methemoglobins did not show any prooxidative effect. The prooxidative effect of the oxyhemoglobin form is ascribed to its increased sensitivity to form superoxide free radicals when transformed to the methemoglobin form. It is proposed that the structure of the heme pocket of fetal oxyhemoglobin enhances free radical release when compared to adult oxyhemoglobin, This difference may be important in some hematological disorders presented by the newborn. OxyhemoglobitzLipid peroridation

Silybin Dihemisuccinate Protects Rat Erythrocytes Against Phenylhydrazine-Induced Lipid Peroxidation and Hemolysis

“…Studies of the addition of silybin dihemisuccinatc to a mixture of phenylhydrazine (0.85 mM) and free hemoglobin (200 tg/ml) were performed using hemoglobin obtained from lysed erythrocytes by fractionation on a carboxymethyl-Sepharose column as described in (17). The Osmotic fragility test was performed according to Gordon-Smith (18 Because red blood cells metabolism is not oxidative, any increase in oxygen consumption can be ascribed to oxidative reactions between phenylhydrazine and erythrocytes.…”

Actividad del sistema de defensa antioxidante y agresión oxidativa en eritrocitos de recién nacidos de bajo de peso y distintas edades gestacionales

“…27 Nosotros hemos demostrado recientemente en el laboratorio que ambas hemoglobinas humanas tienen una diferente capacidad prooxidante en su estado de oxihemoglobina. 13 Esta hipotesis puede ser cierta ya que la relaci6n entre ambas hemoglobinas (HbF/HbA) disminuye en forma proporcional durante la gestaci6n., siendo mayor en los nifios de pretermino (Grupo II y Grupo III) con respecto a los ninos de termino (Grupo I).…”