Protein profiling formats

Antibody arrays immobilized on glass surfaces mimic DNA microarrays in format and spot size. The biggest challenge in protein profiling using antibody microarrays is selection of validated antibodies that are useful in the desired sample environment. Many of the initial reports used antibody arrays assayed for cytokines because serum presents a relatively simple sample assay environment compared to tissue and also because there are numerous validated antibodies available for this clinically important set of proteins. Tissue and cell lysates present more complex assay environments with more opportunities for antibody cross-reactivity and other interferences which erode the biological meaningfulness of the data. 

Human development begins from an embryo, which is the result of cell proliferation and differentiation that led to the formation of more than 700 cell types containing over a trillion cells as an adult. Each cell type contains the same genome but a different proteome because of the differential expression of genes that characterize the structure and function of a particular cell type thus, a neuron cell is much different from a muscle cell. These cell types have an entirely different protein profile that gives the neuron cell and the muscle cell their characteristic structure and function. These two cell types differ in many proteins. Several cell types predominantly produce only a few but different proteins. For example, the beta cells of the pancreas predominantly make insulin, whereas the erythrocytes make hemoglobin... 

The formol index (total free amino acids) was the best predictor of browning rate of concentrates during storage for a given commodity. While haze and sediment formation were quality factors of major interest in this study, none of the juices or concentrates produced were particularly troublesome in this regard. The phenolic and protein profiles should still provide a reference with which unstable experimental or commercial samples can be compared in the future, however. In addition to color and appearance, quality factors of flavor, astringency, bitterness, viscosity and mouthfeel warrant investigation. 

Figure 2. Analysis of cellular proteins from Helicobacter pylori strain 26695 (A) and a recent clinical isolate of H. pylori (B). Bacterial proteins prepared by lysis of the cells with detergent were analysed on small format 2-dimensional gel (Cash and Kroll, 2003) and the resolved proteins stained with silver. Arrows indicate a few of the protein differences detected by manual inspection of the protein profiles.

Approaches aimed at achieving quantitative protein profiling using antibody arrays in a multiplex format include signal amplification, multicolor detection and competitive displacement assays (Barry and Soloviev, 2004). If the use of antibodies for protein microarrays is to be materialized, several important criteria have to be fulfilled ... 

Triazole Formation-Based Bioconjugation for Activity-Based Protein Profiling... 

Agonists can produce complex binding profiles due to the formation of different protein species (i.e., ternary complexes with G-proteins). The extent of this phenomenon is related to the magnitude of agonist efficacy and can be used to quantify efficacy. 

The translational diffusion coefficient in Eq. 11 can in principle be measured from boimdary spreading as manifested for example in the width of the g (s) profiles although for monodisperse proteins this works well, for polysaccharides interpretation is seriously complicated by broadening through polydispersity. Instead special cells can be used which allow for the formation of an artificial boundary whose diffusion can be recorded with time at low speed ( 3000 rev/min). This procedure has been successfully employed for example in a recent study on heparin fractions [5]. Dynamic fight scattering has been used as a popular alternative, and a good demonstra-... 

However, there are a number of other miscellaneous biological roles played by this complex. The [Co(NH3)6]3+ ion has been shown to inhibit the hammerhead ribozyme by displacing a Mn2+ ion from the active site.576 However, [Co(NH3)6]3+ does not inhibit ribonuclease H (RNase),577 topoisomerase I,578 or hairpin ribozyme,579 which require activation by Mg2+ ions. The conclusions from these studies were that an outer sphere complex formation between the enzyme and Mgaq2+ is occuring rather than specific coordination of the divalent ion to the protein. These results are in contrast to DNase I inhibition by the same hexaammine complex. Inhibition of glucose-induced insulin secretion from pancreatic cells by [Co(NH3)6]3+ has been found.580 Intracellular injection of [Co(NH3)6]3+ into a neurone has been found to cause characteristic changes to the structure of its mitochondria, and this offers a simple technique to label neuronal profiles for examination of their ultrastructures.581... 

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