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Protein-bound

Goldanskii V I and Krupyanskii Y F 1989 Protein and protein-bound water dynamics studied by Rayleigh scattering of Mdssbauer radiation (RSMR) Q. Rev. Biophys. 22 39-92... [Pg.2847]

Most potentiometric electrodes are selective for only the free, uncomplexed analyte and do not respond to complexed forms of the analyte. Solution conditions, therefore, must be carefully controlled if the purpose of the analysis is to determine the analyte s total concentration. On the other hand, this selectivity provides a significant advantage over other quantitative methods of analysis when it is necessary to determine the concentration of free ions. For example, calcium is present in urine both as free Ca + ions and as protein-bound Ca + ions. If a urine sample is analyzed by atomic absorption spectroscopy, the signal is proportional to the total concentration of Ca +, since both free and bound calcium are atomized. Analysis with a Ca + ISE, however, gives a signal that is a function of only free Ca + ions since the protein-bound ions cannot interact with the electrode s membrane. [Pg.489]

Fig. 8. A simplified combinatorial approach to identify the binding sequence for a (O) protein of interest, within 4096 sequences where ( ) represents the PCR primers, N a nucleotide, ie. A, G, C, or T. An essential aspect of this experiment is the abiHty to separate protein-bound from free DNA prior to... Fig. 8. A simplified combinatorial approach to identify the binding sequence for a (O) protein of interest, within 4096 sequences where ( ) represents the PCR primers, N a nucleotide, ie. A, G, C, or T. An essential aspect of this experiment is the abiHty to separate protein-bound from free DNA prior to...
The absorption of sulfonylureas from the upper gastrointestinal tract is faidy rapid and complete. The agents are transported in the blood as protein-bound complexes. As they are released from protein-binding sites, the free (unbound) form becomes available for diffusion into tissues and to sites of action. Specific receptors are present on pancreatic islet P-ceU surfaces which bind sulfonylureas with high affinity. Binding of sulfonylureas to these receptors appears to be coupled to an ATP-sensitive channel to stimulate insulin secretion. These agents may also potentiate insulin-stimulated glucose transport in adipose tissue and skeletal muscle. [Pg.341]

Structure of the MoFe Protein. Extensive spectroscopic studies of the MoEe proteia, the appHcation of cluster extmsion techniques (84,151), x-ray anomalous scattering, and x-ray diffraction (10,135—137,152) have shown that the MoEe proteia contains two types of prosthetic groups, ie, protein-bound metal clusters, each of which contains about 50% of the Ee and content. Sixteen of the 30 Ee atoms and 14—16 of the 32—34... [Pg.88]

Although FeMo-cofactor is clearly knpHcated in substrate reduction cataly2ed by the Mo-nitrogenase, efforts to reduce substrates using the isolated FeMo-cofactor have been mosdy equivocal. Thus the FeMo-cofactor s polypeptide environment must play a critical role in substrate binding and reduction. Also, the different spectroscopic features of protein-bound vs isolated FeMo-cofactor clearly indicate a role for the polypeptide in electronically fine-tuning the substrate-reduction site. Site-directed amino acid substitution studies have been used to probe the possible effects of FeMo-cofactor s polypeptide environment on substrate reduction (163—169). Catalytic and spectroscopic consequences of such substitutions should provide information concerning the specific functions of individual amino acids located within the FeMo-cofactor environment (95,122,149). [Pg.90]

Body fluids are analyzed for T and T by a variety of radioimmunoassay procedures (31) (see Immunoassays). The important clinical parameter for estimating thyroid function, the protein-bound iodine (PBI), is measured as described in treatises of clinical chemistry. High performance Hquid chromatographic (hplc) methods have replaced dc (32,33). [Pg.51]

Proteins may consist exclusively of a polymeric chain of amino acids these are the simple proteins. Quite often some other chemical component is covalendy bonded to the amino acid chain. Glycoproteins and Hpoproteins contain sugar and Hpid components, respectively. Porphyrins are frequently associated with proteins, eg, in hemoglobin. Proteins bound to other chemical components are called conjugated proteins. Most enzymes are conjugated proteins. [Pg.94]

Disopyr mide. Disopyramide phosphate, a phenylacetamide analogue, is a racemic mixture. The dmg can be adininistered po or iv and is useful in the treatment of ventricular and supraventricular arrhythmias (1,2). After po administration, absorption is rapid and nearly complete (83%). Binding to plasma protein is concentration-dependent (35—95%), but at therapeutic concentrations of 2—4 lg/mL, about 50% is protein-bound. Peak plasma concentrations are achieved in 0.5—3 h. The dmg is metabolized in the fiver to a mono-AJ-dealkylated product that has antiarrhythmic activity. The elimination half-life of the dmg is 4—10 h. About 80% of the dose is excreted by the kidneys, 50% is unchanged and 50% as metabolites 15% is excreted into the bile (1,2). [Pg.113]

Mexifitene is well absorbed from the GI tract and less than 10% undergoes first-pass hepatic metabolism. In plasma, 60—70% of the dmg is protein bound and peak plasma concentrations are achieved in 2—3 h. Therapeutic plasma concentrations are 0.5—2.0 lg/mL. The plasma half-life of mexifitene is 10—12 h in patients having normal renal and hepatic function. Toxic effects are noted at plasma concentrations of 1.5—3.0 lg/mL, although side effects have been noted at therapeutic concentrations. The metabolite, /V-methy1mexi1itene, has some antiarrhythmic activity. About 85% of the dmg is metabolized to inactive metabolites. The kidneys excrete about 10% of the dmg unchanged, the rest as metabolites. Excretion can also occur in the bile and in breast milk (1,2). [Pg.113]

Encainide is almost completely absorbed from the GI tract. Eood may delay absorption without altering its bioavailabiUty. The dmg is rapidly metabolized in 90% of the patients to two principal metaboUtes, 0-demethylencainide (ODE) and 3-methoxy-O-demethylencainide (MODE), while the other 10% metabolize encainide slowly with Htde or no ODE or MODE formed. Encainide, ODE, and MODE are extensively protein bound 75—80% for encainide and ODE and 92% for MODE. Peak plasma concentrations are achieved in 30—90 min. Therapeutic plasma concentrations are very low the concentrations of ODE and MODE are approximately five times those of encainide. The findings with the metaboUtes are significant because ODE is 2—10 times and MODE, 1—4 times more effective than encainide as antiarrhythmics. The half-Hves for encainide in fast and slow metabolizers is 1—2 h and 6—12 h, respectively. The elimination half-life for ODE is 3—4 h and for MODE 6—12 h in fast metabolizers. Excretion occurs through the Hver and kidneys (1,2). [Pg.114]

About 97% of po dose is absorbed from the GI tract. The dmg undergoes extensive first-pass hepatic metaboHsm and only 12% of the po dose is bioavailable. More than 95% is protein bound and peak plasma concentrations are achieved in 2—3 h. Therapeutic plasma concentrations are 0.064—1.044 lg/mL. The dmg is metabolized in the Hver to 5-hyroxypropafenone, which has some antiarrhythmic activity, and to inactive hydroxymethoxy propafenone, glucuronides, and sulfate conjugates. Less than 1% of the po dose is excreted by the kidney unchanged. The elimination half-life is 2—12 h (32). [Pg.114]

Because bretylium is poody absorbed from the GI tract (- 10%), it is adrninistered iv or im. Very litde dmg is protein bound in plasma. Bretylium is taken up by an active transport mechanism into and concentrated in postganglionic nerve terminals of adrenergicahy innervated organs. Peak plasma concentrations after im injections occur in about 30 min. Therapeutic plasma concentrations are 0.5—1.0 p.g/mL. Bretylium is not metabolized and >90% of the dose is excreted by the kidneys as unchanged dmg. The plasma half-life is 4—17 h (1,2). [Pg.121]

Nicardipine is almost completely absorbed after po adrninistration. Administration of food decreases absorption. It undergoes extensive first-pass metaboHsm in the Hver. Systemic availabiHty is dose-dependent because of saturation of hepatic metaboHc pathways. A 30 mg dose is - 35% bioavailable. Nicardipine is highly protein bound (>95%). Peak plasma concentrations are achieved in 0.5—2.0 h. The principal path of elimination is by hepatic metaboHsm by hydrolysis and oxidation. The metaboHtes are relatively inactive and exert no pharmacological activity. The elimination half-life is 8.6 h. About 60% of the dose is excreted in the urine as metaboHtes (<1% as intact dmg) and 35% as metaboHtes in the feces (1,2,98,99). [Pg.126]

Absorption of nadolol after po dosing is variable, averaging about 30%. The presence of food does not affect absorption. There is no hepatic first-pass metabolism and peak plasma concentrations are achieved in 3—4 h after po doses. About 30% of the plasma concentration is protein bound. The elimination half-hfe of nadolol is 20—24 h, allowing once a day dosing. The dmg is excreted unchanged by the kidneys and its excretion is delayed in patients having renal failure (98,99,108). [Pg.127]

It has also been possible to determine the x-ray structures of classic zinc finger motifs from several proteins bound to specific DNA fragments. We will here describe one such structure containing three zinc fingers from a mouse protein, Zif 268, which is expressed at an early developmental stage of the mouse. Nikola Pavletich and Carl Pabo at the Johns Hopkins University School of Medicine, Baltimore, determined the x-ray structure to 2.1 A resolution of a recombinant polypeptide derived from Zif 268 bound to a 10-base... [Pg.177]

Cadmium is effectively accumulated in the kidneys. When the cadmium concentration exceeds 200 gg/g in the kidney cortex, tubular damage will occur in 10% of the population, and proteins begin to leak into urine (proteinuria). When the concentration of cadmium in the kidney cortex exceeds 300 pg/g, the effect is seen in 50% of the exposed population. Typically, excretion of low-molecular weight proteins, such as beta-microglobulin, is increased, due to dysfunction of proximal tubular cells of the kidney. The existence of albumin or other high-molecular weight proteins in the urine indicates that a glomerular injury has also taken place. The excretion of protein-bound cadmium will also be increased. [Pg.269]

Disopyramide anti-airhythmic, S(+)-isomer more sb ongly protein bound... [Pg.319]

Fatty acids are synthesized by a nrultistep route that starts with acetate. The first step is a reaction between protein-bound acetyl and malonyl units to give a protein-bound 3-ketobutyryl unit. Show the mechanism, and tell what kind of reaction is occurring. [Pg.1099]

If there is a means to detect (i.e., radioactivity, fluorescence) and differentiate between protein-bound and free ligand in solution, then binding can directly quantify the interaction between ligands and receptors. [Pg.73]

In tissues, most coelenterazine exists in a protein-bound stabilized form, which liberates free coelenterazine when extracted with methanol. Thus, the amount of coelenterazine measured by this method is the sum of free coelenterazine and its protein-bound form. [Pg.364]

Two types of stabilized coelenterazine are known to exist in biolu-minescent organisms, i.e. the protein-bound form (usually bound to a calcium-binding protein) and the enol ester form (usually enol-sulfate see Structure I, Fig. 5.5). [Pg.365]

The assay result of coelenterazine described in Section C5.1 includes the amount of the protein-bound form of coelenterazine in addition to free coelenterazine. The assay of only the protein-bound form, or only the free coelenterazine, is complicated because the protein-bound form tends to liberate free coelenterazine by various stimuli, not only by Ca2+. An example of the measurement of protein-bound coelenterazine is given by Shimomura and Johnson (1979b). [Pg.365]

Dacarbazine is activated by photodecomposition (chemical breakdown caused by radiant energy) and by enzymatic N-demethylation. Formation of a methyl carbonium ion results in methylation of DNA and RNA and inhibition of nucleic acid and protein synthesis. Cells in all phases of the cell cycle are susceptible to dacarbazine. The drug is not appreciably protein bound, and it does not enter the central nervous system. [Pg.56]

When induced in macrophages, iNOS produces large amounts of NO which represents a major cytotoxic principle of those cells. Due to its affinity to protein-bound iron, NO can inhibit a number of key enzymes that contain iron in their catalytic centers. These include ribonucleotide reductase (rate-limiting in DNA replication), iron-sulfur cluster-dependent enzymes (complex I and II) involved in mitochondrial electron transport and cis-aconitase in the citric acid cycle. In addition, higher concentrations of NO,... [Pg.863]

Figure 3 provides a very general overview of transcriptional activation in response to a PPAR ligand. Fig. 3a shows the schematic representation of a PPAR target gene in the absence of PPAR ligand. Co-repressor proteins bound to both unliganded PPAR and RXR... [Pg.940]

Thyroxine (3, 5, 3,5-L-teraiodothyronine, T4) is a thyroid hormone, which is transformed in peripheral tissues by the enzyme 5 -monodeiodinase to triiodothyronine. T4 is 3-8 times less active than triiodothyronine. T4 circulates in plasma bound to plasma proteins (T4-binding globulin, T4-binding prealbumin and albumin). It is effective in its free non-protein-bound form, which accounts for less than 1%. Its half-life is about 190 h. [Pg.1201]

Triiodothyronine (3, 5,3-L-triiodothyronine, T3) is a thyroid hormone. It is producedby outer ring deiodination of thyroxine (T4) in peripheral tissues. The biologic activity of T3 is 3-8 times higher than that of T4. T3 is 99.7% protein-bound and is effective in its free non-protein-bound form. The half-life of triiodothyronine is about 19 h. The daily tur nover of T3 is 75%. Triiodothyronine acts via nuclear receptor binding with subsequent induction of protein synthesis. Effects of thyroid hormones are apparent in almost all organ systems. They include effects on the basal metabolic rate and the metabolisms of proteins, lipids and carbohydrates. [Pg.1243]

Milk, milk products, and foods of animal origin contain high amounts of (free) riboflavin with good bioavailability. In foods of plant origin, the majority of riboflavin is protein-bound and therefore less bioavail-able. Cereal germs and bran are plant sources rich in riboflavin [1]. [Pg.1289]

IPPB intermittent positive pressure breathing PBI protein-bound iodine... [Pg.648]


See other pages where Protein-bound is mentioned: [Pg.398]    [Pg.2830]    [Pg.397]    [Pg.200]    [Pg.224]    [Pg.50]    [Pg.91]    [Pg.28]    [Pg.120]    [Pg.203]    [Pg.51]    [Pg.680]    [Pg.157]    [Pg.258]    [Pg.410]    [Pg.366]    [Pg.190]    [Pg.190]    [Pg.11]   
See also in sourсe #XX -- [ Pg.24 ]

See also in sourсe #XX -- [ Pg.96 ]




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Absorption of protein-bound vitamin

Albumin bound drugs protein binding

Biological significance of protein-bound carbohydrates

Biotin protein-bound, digestion

Bound water in proteins

Bounded diffusion in proteins

Cadmium protein-bound

Calcium, absorption protein-bound

Carbohydrates protein-bound, biological significance

Characterization of Bound Water at Protein Surfaces the First Hydration Shell

Copper protein-bound

Electron transfer between protein-bound groups

Endoplasmic reticulum membrane-bound proteins

Genetic diseases membrane-bound proteins

Glycogen-bound protein phosphatase

Growth factor receptor-bound protein

Heat shock protein-bound receptors

Heparin-bound protein, effects

Hexose, protein-bound

In membrane-bound proteins

Induced Circular Dichroism of Aromatic Compounds Bound to Proteins

Induced Circular Dichroism of Heme and Chlorophyll Bound to Proteins

Iodine protein-bound

Lipids protein-bound

Lipoic acid protein-bound

Membrane bound protein complex

Membrane-bound diiron proteins

Membrane-bound protein, bacteriorhodopsin

Membrane-bound proteins

Membrane-bound proteins amino acid sequence

Membrane-bound proteins and enzymes

Membrane-bound proteins hormone receptors

Membrane-bound proteins molecular modeling

Membrane-bound proteins sugar transporters

Mercapturic acid protein-bound

Methionine protein-bound

Myelin-bound protein

Peptides that bound target proteins

Protein bound amino acids, racemization

Protein bound carbohydrate

Protein bound mono ADP-ribose

Protein bound toxins

Protein identify peptides that bound target

Protein membrane-bound, purification

Protein molecules with bound lipid

Protein-bound Amadori compounds

Protein-bound calcium

Protein-bound clusters

Protein-bound drug

Protein-bound oligosaccharides, structural

Protein-bound redox, generation

Protein-bound rhodium hydrogenation

Protein-bound rhodium hydrogenation catalyst

Protein-bound, biological significance

Proteins chlorophyll bound

Proteins, aromatic compounds bound

Purification of a Membrane-Bound Protein

Silica protein-bound

Starch granule-bound proteins

Surface-bound protein

The Reactive Chlorophyll Is Bound to Proteins in Reaction Centers

Thyroxine protein bound

Uremic toxins protein bound

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