Detergents deoxycholate

In 1957, we reported on the use of the detergent deoxycholate for the solubilization of aminoazo dye N-demethylase, and we also reported an inhibitory effect of CO on aminoazo dye N-demethylase activity (49). In a key study in 1968, Lu Coon described the deoxycholate-dependent solubilization and resolution of a liver microsomal fatty acid >-hydroxylation system into three components by column chromatography, and they were able to reconstitute catalytic activity by combining the three fractions (50). The three fractions were identified as cytochrome P450,... 

Some precautions should be taken during the isolation of membrane-bound polysomes. For example, some D-RNPs, including nuclear 308 particles, are not stable and dissociate in the presence of the anionic detergent deoxycholate. The nonionic... 

Modeling Pardaxin Channel. The remarkable switching of conformation in the presence of detergents or phospholipid vesicles (5) suggests that pardaxin is a very flexible molecule. This property helps to explain the apparent ability of pardaxin to insert into phospholipid bilayers. In addition, it is consistent with the suggestion that the deoxycholate-like aminoglycosteroids (5,7) present in the natural secretion from which pardaxin is purified (5) serve to stabilize its dissociated conformation. The question of the mechanism by which pardaxin assembles within membranes is important for understanding pore formation and its cytolytic activity (5). 

A similar activity level was obtained in the deoxycholate, Triton X-100, and NP-40 extract preparations. Octyl glucoside and CHAPS extract preparations showed no detectable prephenate aminotransferase activity. When the hemoglobin step was used, there was no increase in the soluble activity recovered in the initial supernatant fraction, but the specific activity of the deoxycholate (the only detergent tried in this experiment) extract increased about tenfold. We would anticipate equally good results with use of Triton X-100 or NP-40 in combination with the hemoglobin step. 

Detergents. Under appropriate conditions of pH, ionic strength and temperature, detergents (ionic sodium lauiyl sulphate, sodium deoxycholate, sodium cholate and cetyldiethyl-ammonium bromide, or nonionic Tweens and Tritons), can be used to lyse cells. Detergents may however cause enzyme inactivation and may need to be removed before purification. 

For some studies, washed lipid globules can be used as such. More commonly, it is necessary to dissociate membranes from globules by chemical or physical methods. Chemical methods normally involve direct extraction of constituents from the globules. Sodium dodecyl sulfate solutions have been used to recover membrane proteins from washed lipid globules for subsequent electrophoretic characterization (Kobylka and Carraway 1972 Mather and Keenan 1975). Other workers have used solutions of detergents such as deoxycholate (Hayashi and Smith 1965) and Triton X-100 (Patton 1982). With these deter-... 

Sodium deoxycholate is a detergent that releases proteins from membranes. 

A deoxycholate-trichloroacetic acid protein precipitation technique that provides for rapid recover of soluble and membrane bound proteins from interfering substances. Interference by lipids and nonionic or cationic detergents is alleviated by adding SDS. 

In 1954, Beaufay and de Duve (27) first suggested a relationship between microsomal phospholipid and glucose-6-phosphatase. They observed a loss of enzymic activity from phospholipid-rich microsomal preparations concomitant with extraction with such organic solvents as butanol or treatment with lecithinase. Various studies were carried out to demonstrate that the latter effect was not produced through inhibition of enzymic activity by accumulated products of the hydrolysis of phospholipids. On the basis of their observations that deoxycholate treatment labilized microsomes to phospholipase action, they concluded that . . . the detergent did not exert its primary effect on the dissociation of phospholipids from microsomal protein, but that it probably disrupted... 

Phosphotransferase activity of the enzyme has been found to respond much more extensively than does phosphohydrolase activity to detergent treatment (see, for example, references 86, 89, 92). This observation led us to investigate in detail alterations in catalytic properties of both phosphotransferase and phosphohydrolase activities produced by detergent treatment. Deoxycholate supplementation has been found to shift the pH optimum of PPi-glucose phosphotransferase from approximately 4.5 noted with fresh microsomal suspensions to approximately pH 5.7 with optimal (0.20%, w/v) deoxycholate concentrations added to micro-somes (see Fig. 2 and references 80 and 98). Preparations obtained by... 

Detergents (26, 41, 46, 96, 97) Optimal concentrations of deoxycholate, cholate, Triton X-100, and cetyltri-methylammonium bromide activate, as does urea. Activation of phosphotransferase > that of phosphohydrolase. Supraoptimal levels inhibit, as do all tested concentrations of sodium lauryl sulfate and Tweens 20 and 80. (See also Lysolecithin, Fatty acids, and Long-chain fatty acyl-CoA esters, above)... 

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