Cellular location

Enzyme Cellular Location Reaction Cofactor Phase OSAR Pharmacophore Homology models Crystal structures... 

Cellular location Tissue Species of MW amino (Da) acids Sequence References... 

Genes for protein whose cellular location is unclear ... 

IV. Superoxide dismutase (EC 1.15.1.1) Within a cell the superoxide dismutases (SODs) constitute the first line of defense against ROS. Superoxide radical (02) is produced where an electron transport chain is present, as in mitochondria and chloroplasts, but 02 activation may occur in other subcellular locations such as glyoxysomes, peroxisomes, apoplast and the cytosol. Thus SODs are present in all these cellular locations, converting superoxide into hydrogen peroxide and water (i.e. copper/zinc SODs are typically found in the nuclei and cytosol of eukaryotic cells). 

The advantage of such co-purification protocols is that the fully processed protein serving as the bait can allow interactions in a native environment and cellular location to allow isolation of multicomponent complexes. One limitation with this approach is the necessity for an antibody with specific immunoreactivity and immunoprecipitative capability for the bait protein. This drawback can be addressed by expression of the protein with an epitope tag. Excellent antibodies to a variety of epitope tags are available and can be utilized for immunoaffinity purification. Tags such as 6-histidine and GST allow purification using affinity characteristics to nickel and GSH beads, respectively. 

Squaraine rotaxane dyes also were utilized as extremely bright and highly stable NIR fluorescent probes for in vitro and in vivo optical imaging of live and fixed cells [55]. These probes were modified for targeting of different cellular locations, namely,... 

Cedano, J., Aloy, P., Perez-Pons, J. A., and Querol, E. (1997). Relation between amino acid composition and cellular location of proteins. J. Mol. Biol. 266, 594—600. 

Pathway Principal tissue/organ Sub-cellular location Section... 

Lung resistance protein Lung resistance protein (LRP) is expressed in normal human bronchial epithelium (NHBE) as well as in other tissues potentially exposed to toxins [104], LRP was reported to be expressed in both Calu-3 cells [105] and 16HBE14o- model [70], However, the role of LRP in different cellular locations is not clear to date. 

Hydrogenases are found in different cellular locations ranging from the cytoplasm, the periplasm, the cytoplasmic and thylakoid membranes and the hydrogenosomes present in a few eukaryotes. 

The production of chimeric cDNA molecules is typically used to localize an amino acid domain in a protein that gives rise to a specific property that is absent in a homologous protein. For example, this property could be the recognition of a specific drug, interaction with a specific protein, or localization to a specific cellular location. Chimeras are often a necessary first step in the path of identifying individual... 

Table 1 Immunomodulatory activities and cellular locations of a subset of natural host defense peptides... 

Peptide Origin Cellular location Immunomodulatory activity Proposed receptors... 

Protein prenylation leads to an increased hydrophobicity of proteins, typically resulting in an increased affinity for membranes. In 2004 studies on the cellular location of prenylated RhoB proteins showed that RhoB can undergo farnesylation (RhoB-F) as well as geranylgeranylation (RhoB-GG). With the aid of specific prenyl transferase inhibitors, it was revealed that RhoB-GG is localized to multivesicular late endosomes. 

When older proteins are broken down in the body, they must be replaced. This concept is called protein turnover, and different types of proteins have very different turnover rates. Protein synthesis occurs during the process of translation on ribosomes. Protein breakdown occurs generally in two cellular locations ... 

DNA stores the genetic information for a cell, but it is RNA that participates in the processes by which this information is used. RNA molecules are classihed according to their function or cellular location. Three major forms are found in prokaryotic cells ... 

Additionally, the cellular location at which the resultant polypeptide will function often cannot be predicted from RNA detection/sequences nor can detailed information regarding how the polypeptide product s functional activity will be regulated (e.g. via post-translational mechanisms such as phosphorylation, partial proteolysis, etc.). Therefore, protein-based drug leads/targets are often more successfully identified by direct examination of the expressed protein complement of the cell, i.e. its proteome. Like the transcriptome (total cellular RNA content) and in contrast to the genome, the proteome is not static with changes in cellular... 

FIGURE 2.6 The ROS probe dihydrorhodamine (DHR) is non-fluorescent until it reacts with ROS to form fluorescent rhodamine-123 (R1230). DHR is not a selective reactant and may react with many other ROS than those listed above. It also does not localize in nuclei nor in cell membranes and cannot identify if ROS are generated in these regions on keratinocytes. Other ROS prohes may prove to he useful to provide more data on these cellular locations. 

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