Hemoglobin rates

The automated method differs from the ICSH method chiefly in that oxidation and ligation of heme iron occur after the hemes have been released from globin. Therefore, ferricyanide and cyanide need not diffuse into the hemoglobin and methemoglobin, respectively. Because diffusion is rate-limiting in this reaction sequence, the overall reaction time is reduced from approximately three minutes for the manual method to 3 —15 seconds for the automated method. Reaction sequences in the Coulter S + II and the Technicon H 1 and H 2 are similar. Moreover, similar reactions are used in the other Coulter systems and in the TOA and Unipath instmments. 

One Anson unit is the amount of enzyme that, under standard conditions, digests hemoglobin at an initial rate, Hberating per minute an amount of TCA-soluble product which produces the same color with phenol reagent as one milliequivalent of tyrosine (91). 

Unzai S et al Rate constants for O2 and CO binding to the alpha and beta subunits within the R and T states of human hemoglobin. J Biol Chem 1998 273 23150. 

Superoxide is formed (reaction 1) in the red blood cell by the auto-oxidation of hemoglobin to methemo-globin (approximately 3% of hemoglobin in human red blood cells has been calculated to auto-oxidize per day) in other tissues, it is formed by the action of enzymes such as cytochrome P450 reductase and xanthine oxidase. When stimulated by contact with bacteria, neutrophils exhibit a respiratory burst (see below) and produce superoxide in a reaction catalyzed by NADPH oxidase (reaction 2). Superoxide spontaneously dismu-tates to form H2O2 and O2 however, the rate of this same reaction is speeded up tremendously by the action of the enzyme superoxide dismutase (reaction 3). Hydrogen peroxide is subject to a number of fates. The enzyme catalase, present in many types of cells, converts... 

Changes in the quantities of the various normal hemoglobin components during developmental stages can be explained in terms of ill-defined regulatory mechanisms which control the rate of synthesis of the polypeptide chains. Such mechanisms have to... 

The Determination of Fetal Hemoglobin (Hb-F). Specific properties of Hb-F have given rise to various methods for Its detection and quantitation which are based on electrophoretic and chromatographic mobilities of Hb-F, on Its slow rate of... 

A total hemoglobin concentration of 0 6 to 0 8 mg/ml Is required Table III presents characteristic spectral maxima observed for the known methemoglobln variants Some methemoglobln variants vary In the rate of reaction with KCN ... 

Ulcerative colitis Leukocytosis, decreased hematocrit/hemoglobin, elevated erythrocyte sedimentation rate (ESR), guaiac-positive stool, (+) perinuclear antineutrophil cytoplasmic antibodies (pANCA up to 70% of patients)... 

It has been proposed that a major source of oxygen radicals in sickle erythrocytes is mutant hemoglobin HbS. However, although HbS showed an accelerated autoxidation rate under in vitro conditions, its in vivo oxidative activity was not determined. Sheng et al. [401] suggested that the observed oxidation rate of HbS is exaggerated by adventitious iron. Dias-Da-Motta et al. [402] proposed that another source of enhanced superoxide production in sickle cells are monocytes in contrast, there is no difference in superoxide release by sickle... 

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