Bovine serum albumin labelling with

Fig. 46. Sum S(t) and difference D(t) curves for Bovine Serum Albumin labeled with DNS in aqueous solution at pH 7.2 S(t) - upper curve, Dlt) - hiver curve. Points are experimental data,...

Serum albumin labeled with an iodine radionuclide was firstly used as a substrate for determining protease activity by Absolon This method was later on modified several times and applied for assaying various proteolytic activities in different materials. Mego et al. injected denaturated I-human %rum albumin into the tail vein of rats and measured the rate of intralysosomal proteolysis on isolated lysosomes containing endocytosed substrate. This method was also used for the determining the intralysosomal pH on the basis of differences found in the rate of I-albumin breakdown in intact and lysed lysosomes C-bovine serum albumin, I-casein or I-albumin have been alternatively used as substrate for measuring the activity of trypsin, chymotrypsin and papain - ). 

Polnaszek and Bryant (1984a,b) measured the frequency dependence of water proton relaxation for solutions of bovine serum albumin reacted with a nitroxide spin label (4.6 mol of nitroxide per mol of protein). The relaxation is dominated by interaction between water and the paramagnetic spin label. The data were best fit with a translational diffusion model, with the diffusion constant for the surface water in the immediate vicinity of the nitroxide being five times smaller than that for... 

Fig. 21. Chemical procedure for labeling bovine serum albumin (MA) with In and destruction of In-BSA...

Some work has been completed on reaction of proteins with nitrite followed by hydrolysis and analysis for amino acids It has been shown that 3-nitrotyrosine and 3,4-dihydroxyphenylalanine are formed from bovine serum albumin when nitrosation occurs under conditions similar to those found in the human stomach (36), Direct demonstration that nitrite reacts with protein has been made by using NaN02 with bovine serum albumin (pH 5.5, 20 C and 200 ppm nitrite). A 60% loss of the originally added nitrite was observed in one week and nearly half of the nitrite (labelled %) could be recovered from the protein. Similar work with myosin revealed that 10-20% of the incorporated label was present as 3-nitrotyro-sine (J7). 

Figure 5. Fluorescence anisotropy of F-D labelled heparin-antithrombin interaction. F-D-heparin (0.02 fluoresceins per uronic acid) at 0.1 mg/ml was incubated with different concentrations of antithrombin (open circles) or bovine serum albumin (solid diamonds) in 20 mM sodium phosphate buffer, pH 7.4.

The flux of 3H-labeled PNU-78,517 across MDCK cell monolayers shows the characteristic disparity between the kinetics of disappearance from the donor solution and appearance in the receiver sink (Fig. 32). Drug uptake is rapid and exponential with time and approaches a quasi-equilibrium state in contrast, the concomitant efflux of drug into the receiver is slow and linear. While maintaining a 3% bovine serum albumin (BSA) concentration in the donor and varying the BSA concentration between 0.5 and 5% in the receiver, the results show that the... 

The concept is demonstrated for a simultaneous immunoassay of (32-microglobulin, IgG, bovine serum albumin, and C-reactive protein in connection with ZnS, CdS, PbS, and CuS colloidal crystals, respectively (Fig. 14.6). These nanocrystal labels exhibit similar sensitivity. Such electrochemical coding could be readily multiplexed and scaled up in multiwell microtiter plates to allow simultaneous parallel detection of numerous proteins or samples and is expected to open new opportunities for protein diagnostics and biosecurity. 

In the method shown in Figure 9A, a biotin-labeled cDNA probe is first immobilized to a polyvinylchloride microtiter plate well that is coated with bio-tinylated-bovine serum albumin [33], The target DNA is hybridized in the liquid-phase with a digoxigenin-labeled probe, so that the biotin-labeled probe can capture a marker enzyme. An antibody-conjugated enzyme is then added, followed by a chemiluminescent substrate. 

When larvae were exposed to an equivalent concentration of radio-labeled naphthalene complexed with bovine serum albumin (BSA), the maximum value for accumulated metabolites was 21%. Radio-labeled naphthalene was almost entirely depurated in 24-36 hr, whereas metabolic products were strongly resistant to depuration... 

A generic enzyme immunoassay for the determination of several synthetic corticosteroids including dexamethasone, betamethasone, flumethasone, triamcinolone, prednisolone, and methylprednisolone in milk, liver, kidney, and muscle samples was recently developed (156). Antibodies raised against dexamethasone-21-hemisuccinate-bovine serum albumin were used in this assay, whereas dexa-methasone-horseradish peroxidase was the label conjugate. Skimmed milk could be directly screened for the presence of corticosteroids at limits of detection of 0.1 ppb for dexamethasone, betamethasone, and flumethasone, 0.3 ppb for triamcinolone and 0.5 ppb for prednisolone. Tissue samples were submitted, prior to the immunoassay, to an extraction/cleanup procedure involving liquid-liquid partitions with acetonitrile-water followed by hexane-chloroform. Background values for bovine liver, swine kidney, and calf muscle were determined to be 0.26, 0.26, and 0.07 ppb, respectively, of dexamethasone equivalents. 

Obtain a precast SDS-polyacrylamide slab gel or prepare one according to instructions in Experiment 4. The recommended gel is 12°/o acrylamide with a thickness of 0.75 mm. Protein samples are prepared as follows Purified proteins (transferrin, bovine serum albumin, a, -antitrypsin, a-lactalbumin from Experiment 4, and molecular weight standards) are supplied in Tris buffer, pH 6.8 solutions at a concentration of 1 mg/mL. Sera samples have been diluted and are ready for use. Prepare protein samples for electrophoresis in 0.5-mL microcentrifuge tubes with attached caps. Label the tubes from 1 to 5 as below or per your Instructor s directions. 

Further application involved collected of fluorescence from dansyl-labeled bovine serum albumin via TIRF optics 150), TIRF-immunoassay for specific dye-labeled antibodies binding from the solution to an antigen-coated surface 151), and a viro-meter — a optical sensor for viruses treated with a fluorescent probe bound to the virus nucleic acid 152,153). 

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