Proteins cell disintegration

Vanadate stimulates protein kinases in the cytosol, as demonstrated in adipose cells and extracts. The activation of a membrane and cytosolic protein tyrosine kinase have been demonstrated in adipocytes, and the membranous enzyme has been postulated to be a way to involve PI-3K actions without activation of insulin receptor substrate-1 (IRS-1) in the insulin signal transduction pathway [140], It is always difficult to determine if protein kinase activation is direct or the result of stimulation of a protein phosphatase. The fact that kinase stimulation was seen in isolated extracts after cell disintegration in this adipocyte cell system supports the idea that vanadium addition to cells could directly stimulate kinases via an as-yet-undetermined mechanism. In other experiments with 3T3-L1 adipocytes bis(acetylacetonato)oxovana-dium (IV) BMOV and bis(l-N-oxide-pyridine-2thiolato)oxovanadium (TV) caused increased tyrosine phosphorylation of both the insulin receptor and IRS-1 in a synergistic way with insulin, as measured by antibodies to phosphotyrosine residues [141]. 

Cumming, R.H. Iceton, G. Cell disintegration and extraction techniques. In Protein Purification Techniques, 2nd Ed. Roe, S., Ed. Oxford University Press Oxford, 2001 83-108. 

Due to the separation of storage compartments from plasm compounds may accumulate within the plant body which are able to denaturate proteins and other compounds necessary for life. The phenolics, for instance, piled up in the sap of vacuoles or in the cell wall are very dangerous to proteins after cell disintegration, i.e., after breaking down compartmentation (B 1.2). 

Geotrichum candidum is a well-known catalyst for asymmetric ketone reductions, and different cell-disintegration methods were used to liberate inuacellular CREDs from these cells. Solid shear (bead milling) proved best. Next, various solid supports were examined for the immobilization of the purified enzyme. The CRED was immobilized on silica with an optimized protein loading of 4 mg/g support. Cross-linking vwth glutaraldehyde rendered the preparation more stable and suitable for use in consecutive batches. This immobilized enzyme was found to be a highly efficient biocatalyst formulation for the production of S(-)-l-(10-naphthyl)ethanol [49]. 

Diphtheria causes a demyelinative neuropathy. Coryne-bacterium diphtheriae colonizes the pharynx or open wounds, and secretes a protein exotoxin. The B subunit of this exotoxin binds to plasma membranes and facilitates entry into cytosol of the A subunit, which catalyzes ADP-ribosylation, and inactivation of an elongation factor required for protein synthesis. Cardiac muscle and Schwann cells are particularly susceptible to this toxin, and hence patients with diphtheria develop cardiomyopathy and demyelinative polyneuropathy [20]. While diphtheria is now uncommon because of childhood immunization against C. diphtheriae, the disruption in preventative medicine programs caused by disintegration of the Soviet Union was followed by a substantial incidence of diphtheritic polyneuropathy in Russia. 

The enzyme proteins were found only in the soluble fraction of disintegrated liver (G10). However, measurable activities of both the enzymes have also been described for isolated cell nuclei (S14, S15). 

Protein content of field peas is negatively correlated with lipid, cell wall material (CWM), sugar, and ash content and positively correlated with starch separation efficiency and protein separation efficiency in air classification of pea flour. The lower separation efficiency of low protein peas may be due to their high lipid and CWM content which makes disintegration of seeds and separation into protein and starch particles by pin milling difficult. It is suggested that peas with a specific protein content should be used in order to control the protein and starch fraction contents (18). 

The nucleus contains almost all of the cell s DNA (around 1% of which is mitochondrial DNA). Together with histones and structural proteins, the nuclear DNA forms the chromatin (see p. 238). it is only during cell division that chromatin condenses into chromosomes, which are also visible with the light microscope. During this phase, the nuclear membrane temporarily disintegrates. 

Various enzymes are produced intracellularly. Hence, following cell harvesting, an efficient disruption process to disintegrate the cell to release the intracellular proteins is needed. Some types of cells are broken readily by gentle treatment, while others are very resistant to breakage. A number of cell disruption methods have been developed ... 

Examples of proteins that are specifically phosphorylated during the cell cycle are the lamins. Hyperphosphorylation of the lamins leads to disintegration of the nuclear lamina. Myosin in actin-myosin filaments is also specifically phosphorylated during mitosis. Other M-phase-specific phosphorylations occur at transcription factor TFIIIB, leading to inhibition of transcription by RNA polymerase III. Phosphorylation of TAP proteins (see 1.4.2.3) is also involved in general inhibition of banscription. 

L. Edebo and K. E. Magnusson, Disintegration of cells and protein recovery, Pure Appl. Chem. 1973, 36, 325-338. 

The bacterium Bacillus thuringiensis forms an internal crystal that contains a number of insecticidal protein toxins. When eaten by the insect, the crystal dissolves in the midgut, the toxin mixture is released, and the proteins are cleaved into active forms. The toxins bind specifically to midgut cells and assemble a pore that leads to disintegration of the cells, gut paralysis, and death. B. thuringiensis strains have toxins specific for caterpillars, beetles, or flies. They have little or no effect on mammals. 

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