CDO1 Human

CDO is a 22.5 kDa protein that contains 200 amino acid residues and has an isoelectric point (pI) of 5.5 . The primary structure of CDO is highly conserved among mammalian species, with only minor differences between murine and human CDO . The enzyme is part of the cupin superfamily, characterized by a 6-stranded β-barrel in a “jelly-roll” topology . Crystal structures of the protein have been obtained at high resolution, providing detailed insights into its active site and overall structure .

The active site of CDO contains iron (II) bound to the cysteine substrate and key residues that facilitate the catalytic process . The enzyme oxidizes cysteine to cysteine sulfinic acid by incorporating dioxygen (O₂), although the exact mechanism of this reaction is still under investigation .

CDO is highly expressed in the liver and placenta, with lower expression levels in the heart, brain, and pancreas . It is also detectable in hepatoblastoma HepG2 cells . The enzyme is a vital regulator of cellular cysteine concentrations and plays an essential role in maintaining the hepatic concentration of intracellular free cysteine within a narrow range .

By converting cysteine to cysteine sulfinic acid, CDO helps regulate intracellular levels of cysteine and responds to changes in cysteine availability . This regulation is crucial for preventing cysteine toxicity and ensuring proper cellular function . CDO is also involved in the biosynthesis of taurine, a compound important for various physiological processes .

Recombinant human CDO is produced using expression systems such as Escherichia coli (E. coli) . The recombinant protein is typically purified to high levels of purity and is used for research purposes to study the enzyme’s structure, function, and role in various biological processes .

The recombinant human CDO protein is supplied as a filtered solution and is stable for several months when stored at temperatures below -20°C . It is used in various biochemical assays and studies to understand the enzyme’s catalytic mechanisms and its implications in health and disease .

CDO has been implicated in various neurodegenerative diseases and cancers, likely related to cysteine toxicity . Understanding the enzyme’s function and regulation can provide insights into these conditions and potentially lead to therapeutic interventions .