Detergents tween

The following procedure is based on the Vectastain ABC kit from Vector (suppliers appendix). It uses an avidin-biotin complex to attach horseradish peroxidase (HRP) or alkaline phosphatase (AP) to the biotinylated secondary antibody. Avidin-biotin systems are capable of extremely high sensitivity because multiple reporter enzymes are bound to each secondary antibody. In addition, the detergent Tween 20 is a popular alternative to protein blocking agents when using nitrocellulose or PVDF membranes. 

The test for mutagenic activity of the detergent (Tween) extract did not induce any revertants all plate counts were in the range of spontaneous mutation rate, with and without S-9 mix. From the ethanol distillate we got a positive response demonstrated in Table II. In the case of milk-crumb the numbers of induced revertants were about a hundredfold those of the spontaneously reverted colonies with the most sensitive strains (TA 98, 100) only without metabolic activation. In the same experiment the test strain TA 100 responded to the soya-crumb sample, also only without metabolic activation. 

In some cases optimal results may be achieved by using the detergent Tween-20 only during the wash after incubation with the final reactant. The reason for this, though, is not well-understood (3). 

The presence of non-ionic detergents (Tween 20, Triton X-100) in the substrate solution is uncommon, but may have a beneficial effect on enzyme activity (Section 10.1.1.4.2). These detergents delay inactivation of the enzyme and increase the optimum temperature... 

Since 1958 when paper electrophoresis of serum proteins was reviewed in this series (P3), there have been no major technical developments in the art. The incorporation of nonionic detergents (Tween 80, Span 20, etc.) in the conventional barbiturate buffer (D14, G18, L14) and the use of tris -borate as buffer (A14, S27) have led to the separation of 7 to 11 globulin fractions. After zone electrophoresis in borate-containing buffer, an increased number of bands can be visualized by staining, but these are not revealed by the schlieren scanning technique after free electrophoresis in similar buffers (S27) the effects of this buffer may be due to interaction between borate and proteins having a high carbohydrate content. 

The Tween separation experiments add further evidence tsupporting this view. The mild detergent Tween 20 solubilizes selectively CPT II from mitochondrial inner membranes but keeps the CPT I bound at the mitochondrial outer membranes. By centrifugation it should be possible then to change significantly the ratio between both CPT-enzymes in the supernatant and the pellet-fraction. As shown in Fig. 2 this is obviously the case. In the supernatant the malonyl-CoA-insensitive fraction increased to 90% of total and decreased to 20% in the pellet fraction. 

FIG. 6 The displacement of bovine p-casein from the surface of a negatively charged PS latex by the nonionic detergent Tween 20, showing that protein displacement is accompanied by a decrease in the thickness of the adsorbed protein layer. (O) Protein coverage ( ) hydrodynamic layer thickness. R is the molar ratio of detergent to protein. 

A measurement setup is build to verify the calculated production of gas during electrolysis according to eq 9. A computer controlled current source (CCCS) is used for electrolysis. The current source is equipped with two current ranges, 0-100 pA and 0-2 mA. The connection holes of the reservoirs are sealed with epoxy (Araldit). The calibration system is then immersed in an electrolyte solution. The electrolyte consists of a 200 mM KNO3 solution to which some detergent (Tween 20) is added. Using a vacuum system, air inside the calibration system is replaced by the electrolyte solution. 

Stutzenberger, F J (1992) Interference of the detergent Tween 80 in protein assays. Anal. Biochem. 207(2) 249-254... 

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