Proteins release

Wu S et al. (2001) Cardiac effects of the extract and active components of Radix stephaniae tetrandrae. I. Electrically induced intracellular calcium transient and protein release during the calcium paradox. Life Sci 68(25) 2853-2861... 

Production of Mucosal Damage 2.3.1.2.1 Cell culture Stimulated neutrophils are known to be cytotoxic to cells in vitro (Dull et al., 1987 Dallegri et al., 1990 Grisham et al., 1990b). Several in vitro systems have been used to demonstrate oxidative damage to intestinal cells. Xanthine/XO increased Cr release and decreased [ H]thymidine uptake by IEC-18 small intestinal epithelial cell monolayers in a dose-dependent manner (Ma et al., 1991). Rat enterocytes show decreased trypan blue exclusion and increased protein release when incubated with neutrophils stimulated... 

T. O. Park, S. Cohen, and R. Langer, Controlled protein release from polyethyleneimine-coated poly(l-lactic acid)/pluronic blend matrices, Pharm. Res, 9, 37 (1992). 

The utility of protein expression mapping using 2D gel electrophoresis and mass spectrometry has been demonstrated for several experimental systems. One application has been to assess the differences in protein expression between normal and cancerous cells. For example, expression mapping has been used to identify protein markers for bladder cancer (Ostergaard et al., 1999). This was accomplished by identifying proteins released into the urine of patients with and without bladder cancer using 2D electrophoresis and mass spectrometry. 

Multiply charged proteins can also be partially sequenced, and microsequences of proteins isolated from several microorganisms have been reported, accomplished with electrospray ionization and FTMS.23,90 Nonadjacent fragment ions may be used to identify bacterial proteins in these top-down strategies.91 In all cases these sequences could be related by bioinformatics to the parent species. An obvious extension would be to characterize proteins from intact microorganisms in this way. In at least one instance a microsequence has been obtained from a protein released from a contaminated intact bacteriophage sample (MS2) to provide a chemotaxonomic identification.77 This work was carried out in an ion trap mass spectrometer. 

Theoretical and model analysis based on a nanofluidic approach is needed for this situation. One may ask, is it possible to release proteins loaded in nanotubules We have found that the addition of the polycation PEI in the release solvent resulted in much quicker protein release, as demonstrated in Figure 14.9. In this case, most of the insulin was released in 1 hour instead of 100 hours. 10-40% of glucose oxidase, catalyse, and hemoglobin were released within 4 hours through complexation with PEI. It is unclear, whether the proteins were replaced by the polycation or released in a complex with PEI. 

To release the pyridine-2-thione leaving group and form the free sulfhydryl, add DTT at a concentration of 0.5 mg DTT per mg of modified protein. A stock solution of DTT may be prepared to make it easier to add it to a small amount of protein solution. In this case, dissolve 20mg of DTT per ml of 0.1M sodium acetate, 0.1M NaCl, pH 4.5. Add 25 pi of this solution per mg of modified protein. Release of pyridine-2-thione can be followed by its characteristic absorbance at 343 nm (s = 8.08 X 103M 1cm 1). 

The anthrax bioterrorist attacks that followed the events of September 11th 2001 resulted in a renewed interest BadUus anthracis, the causative agent of this disease. Research has focused on the development of better vaccines than the one currently available. It has been estimated that the aerosolized release of 100 kg of anthrax spores upwind of Washington DC would cause mortalities of 130,000-3,000,000 [63]. Nonetheless, wild-type Bacillus anthracis is susceptible to conventional antibiotics, including penicillin, oxyfloxacin and ciprofloxacin. The problem lies not with the bacterial infection itself, but with three proteins released by the bacteria - protective antigen (PA, 83 kDa), lethal factor (LF, 90 kDa) and edema factor (EF, 89 kDa) -known as anthrax toxins [63]. 

Theophylline appears to produce bronchodilation by inhibiting phosphodiesterases, which may also result in antiinflammatory and other nonbronchodilator activity through decreased mast cell mediator release, decreased eosinophil basic protein release, decreased T-lymphocyte proliferation, decreased T-cell cytokine release, and decreased plasma exudation. 

In polymorphonuclear leucocytes (PMNL, neutrophils), secretory responses measured as vitamin B -binding protein release were inhibited by feverfew extract when the response was induced by the chemotactic peptide FMLP or arachidonic acid but not when the calcium ionophore A23187 was... 

During the normal process of termination of translation, stop codons are recognized by protein release factors (RF). Although the details of the process are not fully understood, it is believed that when a termination codon reaches the ribosomal A-site, the RF associates with the ribosomal-mRNA complex, inducing the peptidyl-transferase center to hydrolyze the ester bond of the pepti-... 

Termination Three codons (UAA, UAG and UGA) are stop codons which do not code for any amino acid but, instead of attaching to a tRNA molecule, they bind a protein release factor. When one of these factors is encountered by the ribosome, peptidyl transfer is aborted, the completed polypeptide chain released by hydrolysis and the ribosome subunits separate. The N-terminal methionine unit is then removed from the polypeptide chain. 

Growth factors are paracrine or endocrine agents, peptides or proteins, released by one cell to regnlate proliferation in adjacent cells (chapter 12) (Table 21.4). Normal cell proliferation requires the presence of growth factors but proliferation of tumonr cells reqnires either no growth factors or much lower concentrations. There are several different characteristics of tumor cells that enable them to respond to very low concentrations of growth factors ... 

We can conclude that the yeast extract is not a source of contamination but, at the same time, cannot conclude whether these nitrogen fractions come from secreted proteins or from cytosolic proteins released... 

The protein release has discontinuous character and occurs between 22 °C and 32 °C in phosphate buffer. The latter is probably due to charge effects of proteins. 

ITABLE 13.5. Examples of biodegradable polymers tested for sustained protein release... 

Andrianov, A.K. and Payne, L.G. (1998). Protein release from polyphosphazene matrices. Adv. Drug Delivery Rev., 31, 185-196. 

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