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Usage

Uses

Used in Research Applications:
Ubiquitin is used as a research tool for in vitro ubiquitination assays, which help scientists study the process of protein degradation and its regulation. This is important for understanding the molecular mechanisms underlying various cellular processes and diseases.
Used in Western Blotting:
Ubiquitin can also be used as a marker in western blotting, a widely used technique for detecting specific proteins in a sample. Its presence in virtually all eukaryotes makes it a reliable internal control for assessing protein loading and transfer efficiency in western blot experiments.
Used in Pharmaceutical Industry:
Although not explicitly mentioned in the provided materials, ubiquitin's role in protein degradation and its involvement in various cellular processes make it a potential target for drug development. Modulating ubiquitin-dependent pathways could lead to the development of therapies for various diseases, including cancer and neurodegenerative disorders.

Biochem/physiol Actions

Ubiquitin is a small regulatory protein present in eukaryote tissues. Exogenous ubiquitin can stimulate apoptosis in numerous cell lines. E7 protein of human papilloma virus-16 stimulates Retinoblastoma Protein degradation via Ubiquitin-Proteasome Pathway.

Relevant academic research and scientific papers

Real-time hydrogen/deuterium exchange kinetics via supercharged electrospray ionization tandem mass spectrometry

Amide hydrogen/deuterium exchange (HDX) rate constants of bovine ubiquitin in an ammonium acetate solution containing 1% of the electrospray ionization (ESI) "supercharging" reagent m-nitrobenzyl alcohol (m-NBA) were obtained using top-down, electron transfer dissociation (ETD) tandem mass spectrometry (MS). The supercharging reagent replaces the acid and temperature "quench" step in the conventional MS approach to HDX experiments by causing rapid protein denaturation to occur in the ESI droplet. The higher charge state ions that are produced with m-NBA are more unfolded, as measured by ion mobility, and result in higher fragmentation efficiency and higher sequence coverage with ETD. Single amino acid resolution was obtained for 44 of 72 exchangeable amide sites, and summed kinetic data were obtained for regions of the protein where adjacent fragment ions were not observed, resulting in an overall spatial resolution of 1.3 residues. Comparison of these results with previous values from NMR indicates that the supercharging reagent does not cause significant structural changes to the protein in the initial ESI solution and that scrambling or back-exchange is minimal. This new method for top-down HDX-MS enables real-time kinetic data measurements under physiological conditions, similar to those obtained using NMR, with comparable spatial resolution and significantly better sensitivity.

Spatially resolved protein hydrogen exchange measured by subzero-cooled chip-based nanoelectrospray ionization tandem mass spectrometry

Mass spectrometry has become a valuable method for studying structural dynamics of proteins in solution by measuring their backbone amide hydrogen/deuterium exchange (HDX) kinetics. In a typical exchange experiment one or more proteins are incubated in deuterated buffer at physiological conditions. After a given period of deuteration, the exchange reaction is quenched by acidification (pH 2.5) and cooling (0 °C) and the deuterated protein (or a digest thereof) is analyzed by mass spectrometry. The unavoidable loss of deuterium (back-exchange) that occurs under quench conditions is undesired as it leads to loss of information. Here we describe the successful application of a chip-based nanoelectrospray ionization mass spectrometry top-down fragmentation approach based on cooling to subzero temperature (-15 °C) which reduces the back-exchange at quench conditions to very low levels. For example, only 4% and 6% deuterium loss for fully deuterated ubiquitin and β2-microglobulin were observed after 10 min of back-exchange. The practical value of our subzero-cooled setup for top-down fragmentation HDX analyses is demonstrated by electron-transfer dissociation of ubiquitin ions under carefully optimized mass spectrometric conditions where gas-phase hydrogen scrambling is negligible. Our results show that the known dynamic behavior of ubiquitin in solution is accurately reflected in the deuterium contents of the fragment ions.