Binding fraction

The physiologic sequelae of biotin deficiency are almost unexplored. Severe skin lesions, especially seborrheic dermatitis and Leiner s disease (Erythroderma desquamativum or exfoliative dermatitis), were increased in young infants bom of mothers on a restricted diet low in eggs, livers, and other biotin-rich foods. After biotin administration the lesions healed. There are claims that excess biotin produces a fatty liver characterized by heightened cholesterol content. Choline has no effect in the prevention of biotin-fatty livers (G2, M2). In mice with transplanted tumors, both the tumors and the blood levels of biotin are below normal (R8). More recent studies established a protection with avidin, the biotin-binding fraction of egg white, against tumor formation (K4). More data along these lines are still needed for confirmation. 

Plasma protein binding fraction unbound (human) [37] 0.19 0.04... 

Affinity chromatography is a particularly powerful procedure that can be used to purify IgG, subpopulations of IgG, or the antigen binding fraction of IgG present in serum/ascitic fluid/hybridoma culture supernatant. This technique requires the production of a solid matrix to which a ligand, which either has affinity for the relevant IgG or vice versa, has been bound. Examples of ligands useful in this context are ... 

Fig. lA shows the procedure for acidic and neutral hpid preparation. Human brain tissue was homogenized and extracted by using a mixture of chloroform and methanol. Next, the lipid extract was dialyzed and applied to the anion exchange column. Then, the binding fraction... 

IS% of the 14-hydroxy metabolite is excreted in the urine. Biliary excretion of clarithromycin is much lower than that of erythromycin. Clarithromycin is widely distributed into the tissues, which retain much higher concentrations than the plasma. Protein-binding fractions in the plasma range from 65 to 70%. The plasma half-life of clarithromycin is 4.3 hours. 

Triamterene is about 45 to 70% bound to plasma proteins.2 91 Influence of disease on binding of triamterene to plasma proteins has been studied.92 Plasma from uremic patients had a decreased binding of triamterene. Hypoproteinemia and hypoalbuminemia decreased the binding fraction. Drug binding was impaired by cirrhosis also.92... 

Stroud, M. R., Handa, K., Salyan, M. E. K. et al. (1996b) Monosialogangliosides of human myelogenous leukemia HL60 cells and normal human leukocytes. 2. Characterization of E-selectin binding fractions, and structural requirements for physiological binding of E-selectin. Biochemistry, 35, 770-8. 

A comparison of the data resulting from the labeling experiments with permeabilized cells with the data obtained by analysis of the boronate-binding fraction suggests the existence of several ADP-ribosylated nuclear matrix proteins. Beginning with a weak, but distinct electrophoretic band at approximately 300 kD, there are modified proteins at 300,220,140,116,73,69,64,60,51,46,43,41 kD. 

Confusion may arise because in different kits, different forms of counting may be employed. For instance, in those kits which employ counting method (1), a low count indicates a high T3 uptake by TBG, i.e. an increased number of free binding sites (e.g. hypothyroidism). A high count in the binding fraction indicates a low T3 uptake by TBG, i.e. a decreased number of free binding sites. This is found in hyperthyroidism. 

Johnson (1969b, 1970) assumed that phosphorylable sites would be serine-containing proteins. Several car-boxylesters were tested to find a selective substrate able to interact in the same site (able to reduce the speed of [ P]DFP labeling on the mipafox binding fraction). Phenyl-phenyl acetate was selected as that substrate. In other studies, PV was observed to be more selective and has been used for decades for testing the target site, the neurotoxic esterase, and was later called the NTE. NTE has been monitored as the PVase activity resistant to 40 pM paraoxon (20 min) ("B" activity) and sensitive to 40 pM paraoxon plus 60-150 pM mipafox ("C" activity), with NTE as the difference between the activity in condition B and condition C. 

It should be noted that these studies pertain to the influence on a bacterial RNA polymerase of a rat uterine fraction that binds estradiol. These observations may or may not be applicable to the action of this fraction on uterine RNA polymerase, a material that has not yet been adequately purified for satisfactory quantitative studies. The binding fraction has been tested for its effect on the incorporation of UTP- C into RNA by nuclei isolated from rat uteri and was found to be inactive. Nevertheless, it is tempting to consider that the macromolecule that binds estradiol intracellularly plays a role in the control of RNA synthesis and that the steroid-protein complex within the cell is more than a transport system, and is an active regulator of cellular metabolism. 

SopoM, M. L., BisrvAs, D. K., Sen, K. K., and Talwar, G. P. (1968). The inhibition of bacterial ribonucleic acid polymerase by the estradiol-binding fraction from rat uteri. Arch. Biochem. Biophys. in press. 

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