Chemical Name: n-Octyl-β-D-maltopyranoside
Appearance: White powder
Purity: ≥98.0% (GC)
MW: 454.51, C20H38O11Storage Condition: 0-5ºC
Shipping Condition: ambient temperature
phospholipid bilayer is the basic structure of the cell membrane. The
most important functions of cells include transportation of substances,
energy exchange, and transmission of information. These functions are
conducted at the cell membrane by membrane proteins. In membrane
biochemistry research, membrane proteins are solubilized and purified to
study their structure and function. Proteins bound
to cell membranes have hydrophobic sites buried within the phospholipid
bilayers and hydrophilic sites facing toward the water layer.
Detergents are used to isolate large insoluble molecules such as
proteins. Detergents interact with the hydrophobic sites of proteins,
which are then solubilized in the water layer, thus separating membrane
proteins. It is important to choose a detergent that does not disrupt
the bioactivities of target proteins. A detergent requires the following
characteristics to be suitable for isolation of membrane proteins:1. Sufficient protein solubilization capability2. No denaturing or inactivation of proteins3. No interference with protein activities4. No precipitation at 4ºC5. Appropriate critical micelle concentrations (CMC) and micelle size6. No absorption in the UV region7. No toxicity8. Availability of detergent detection methods9. Non-ionic detergent if ion exchange chromatography is usedIn
the past, polyoxyethylene ether non-ionic detergents were widely used.
These detergents, however, had several problems, such as denaturation of
proteins and low CMC value, which cannot be separated easily by
dialysis. n-Octyl-β-D-glucoside, n-Octyl-β-Dthioglucoside, CHAPS, and
CHAPSO eliminate these problems and are widely used today. Most of the
current detergents are non-ionic and easily applied to ion exchange
chromatography purification. deoxy-BIGCHAP is a non-ionic detergent
possessing deoxycholic acid and a gluconamide polar group. It has a high
CMC value of 1.4 mM and can be easily separated by dialysis. Because
its UV absorbance is low, it can be used for the determination of
proteins. deoxy-BIGCHAP has been used for the extraction of opioid
receptors from neuroblastoma or hybrid cells of glyoma. It has also been
applied to adenylate cyclase or acetyltransferase. These detergents are
also widely used to solubilize chromophores or to stabilize enzymes in
diagnostic analyses and biochemical assays. Trials
of various kinds of detergents are needed to find the appropriate
detergent for each study. Dojindo’s Detergent Screening Sets, which
contain assorted packages of detergents, are available for use in these
1. T. Tsukihara, et al., Structures of Metal Sites of Oxidized Bovine Heart Cytochrome c Oxidase at 2.8ÁE Science. 1995;269:1069-1074.
2. S. Iwata, et al., Structure at 2.8ÁEresolution of cytochrome c oxidase from Paracoccus denitrificans. Nature. 1995;376:660-669.
Critical Micelle Concentration (CMC)Detergents are amphipathic compounds, with both lipophobic and lipophilic sites, that will form micelles above a critical concentration that is specific to each detergent. This is called the critical micelle concentration (CMC). The solubilizing abilities of detergents increase dramatically above their CMC values. After extracting membrane proteins, detergents can be easily removed by dilution, and then dialysis.
Table 1 Molecular Weight and Critical Micelle Concentration of Detergents