Impaired erythrocyte methemoglobin reduction in sickle cell disease: dependence of methemoglobin reduction on reduced nicotinamide adenine dinucleotide content
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منابع مشابه
Impaired erythrocyte methemoglobin reduction in sickle cell disease: dependence of methemoglobin reduction on reduced nicotinamide adenine dinucleotide content.
We have examined aspects of methemoglobin (metHb) reduction in sickle and in thalassemic red blood cells (RBCs). NADH metHb reductase activity in sickle and thalassemic RBCs was significantly increased compared with normal RBCs. Because in vitro enzyme activity does not necessarily represent in vivo activity, we measured the rate of metHb reduction in intact RBCs. Intact thalassemic RBCs demons...
متن کاملDecreased erythrocyte nicotinamide adenine dinucleotide redox potential and abnormal pyridine nucleotide content in sickle cell disease.
RBCs from individuals with sickle cell disease are more susceptible to oxidant damage. Because key antioxidant defense reactions are linked to the pyridine nucleotides nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), we tested the hypothesis that the RBC redox potential as manifested by the NADH/[NAD+ + NADH] and NADPH/[NADP+ + NADPH] ratios is dec...
متن کاملProperties of methemoglobin reductase and kinetic study of methemoglobin reduction.
A soluble erythrocyte cytochrome b5 was purified as the substrate of methemoglobin reductase and an electron carrier to methemoglobin. The isoelectric point of this protein was at pH 4.3, and E0' was -0.010 at pH 7.0.. The Km value of the enzyme for this protein was 1 x 10(-4) M, and the turnover number (k5) was 3.4 x 10(4) min-1, with NADH as an electron donor at pH 7.0. The optimum pH of the ...
متن کامل[Regulation of methemoglobin reduction in human erythrocytes].
The regulation of methemoglobin reduction in human erythrocytes was studied in vitro in association with glycolytic reactions, by using hemolysates prepared from the nitrate-treated eryth rocytes. The results obtained are as follows; 1) The addition of cytochrome b5 to the reaction mixture containing fructose 1,6-diphosphate as the substrate for glycolysis caused a marked increase in...
متن کاملThe enthalpy change for the reduction of nicotinamide--adenine dinucleotide.
The heat of the reaction NAD(+)+propan-2-ol=NADH+acetone+H(+) was determined to be 42.5+/-0.6kJ/mol (10.17+/-0.15kcal/mol) from equilibrium measurements at 9-42 degrees C catalysed by yeast alcohol dehydrogenase. With the aid of thermochemical data for acetone and propan-2-ol the values of DeltaH=-29.2kJ/mol (-6.99kcal/mol) and DeltaG(0)=22.1kJ/mol (5.28kcal/mol) are derived for the reduction o...
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ژورنال
عنوان ژورنال: Blood
سال: 1990
ISSN: 0006-4971,1528-0020
DOI: 10.1182/blood.v76.5.1008.1008