Cholesterol Oxidase (CHOD)

Cholesterol Oxidases exist as both type I and type II oxidases and are implicated in bacterial pathogenesis. In addition, they are important as clinical reagents, potential larvicides, and tools in cell biology. Cholesterol esterase catalyzes the hydrolysis of sterol esters into their component sterols and fatty acids. The enzyme is found primarily in the pancreas, but has been detected in other tissues as well. Bile salts, such as cholate and its conjugates, are required to stabilize the enzyme in its native polymeric form and to protect it from proteolytic hydrolysis in the intestine (Vahouny and Treadwell 1968). Cholesterol esterase finds clinical applications in the determination of serum cholesterol (Allain et al. 1974). Cholesterol esterase is synthesized in the acinar cells of the pancreas, stored in zymogen granules, and secreted as a component of pancreatic juice into the lumen of the small intestine (Labow et al. 1983). Cholesterol esterase hydrolyzes a wide range of ester substrates including cholesteryl esters, acylglycerides, phospholipids (Brockerhoff and Jensen 1974), retinyl esters (Fredrikzon et al. 1978), vitamin esters, and phenyl esters (Rudd and Brockman 1984). The enzyme has also been found to have amidase activity (Hui et al. 1993). The enzyme is useful as a biocatalyst because of its ability to catalyze transacylation reactions in a water-limited environment (Gallo et al. 1977, Kazlauskas 1989, and Feaster et al. 1996). Cholesterol esterase is a glycoprotein that in the presence of salts aggregates to a hexamer (Hyun et al. 1971). Cholesterol esterase belongs to the alpha/beta-hydrolase fold family (Ollis et al. 1992, Cygler et al. 1993). Most members of this family are esterases and share secondary and tertiary features. Nearly all use a serine esterase catalytic mechanism, which resembles that of the serine proteases (Kraut 1977). The gene that encodes cholesterol esterase in pigs (lipA) is located on chromosome 14 (GENE ID: 100142668). The LIPA gene is conserved in human, chimpanzee, dog, cow, mouse, rat, chicken, zebrafish, fruit fly, mosquito, C. elegans, S. pombe, S. cerevisiae, E. gossypii, M. grisea, N. cassa, A. thaliana, and rice.||Applications: Suitable for use in ELISA, Western Blotting, Immunoprecipitation. Other applications not tested.||Recommended Dilution: |ELISA: 1:1000 to 1:10,000|Optimal dilutions to be determined by the researcher.||Storage and Stability:|May be stored at 4°C for short-term only. For long-term storage and to avoid repeated freezing and thawing, aliquot and add glycerol (40-50%). Freeze at -20°C. Aliquots are stable for at least 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.