Differential ultracentrifugation

Richards, E.G. and Schachman, H.K. (1957) A differential ultracentrifuge technique for measuring small changes in sedimentation coefficients. Journal of the American Chemical Society, 79,5324—5325. 

Differential ultracentrifugation methods may also be applied to analysis of the purity of macromolecular samples. If one sharp moving boundary is observed in a rotating centrifuge cell, it indicates that the sample has one component and therefore is pure. In an impure sample, each com ponent would be expected to form a separate moving boundary upon sedimentation. 

Human plasma lipoproteins and lipoprotein deficient plasma (LPDS) were prepared from normal plasma of healthy individuals by differential ultracentrifugation on KBr gradients (16). 

Fig. 2.4.13. Left typical amyloid fibrils are twisted / -sheets [27], Right differential ultracentrifugation experiment with A/ (1-42, 33 and 16 xm) in the absence (right) or presence (left) of dimeric aminopyrazole 9 (Ampox, 1 mM). S = solution,...

The biophysical experiments of our cooperation partners focus mainly on two different techniques - a rough estimate of aggregation prevention is found by differential ultracentrifugation (UC), but more detailed information about the kinetics and aggregate size comes from fluorescence correlation spectroscopy (FCS) [24]. 

The results of the respective differential ultracentrifugations correlate very well with the FCS measurements. Without addition of our ligands Afl (1-42) almost completely precipitates and is found exclusively in the pellet (P). Addition of 9 or 20 before the start of the aggregation process keeps most of the protein in solution (S, Figure 2.4.13), however. 

Taylor was unable to separate catheptic from peptic activity, either by ammonium sulfate and sodium chloride precipitation, or by ion-exchange chromatography, free boundary electrophoresis (Fig. 2), or differential ultracentrifugation (T24, T26). 

The majority of these reactions are catalysed by one enzyme system, the cytochromes P-450 monooxygenase system, which is located particularly in the SER of the cell. The enzyme system is isolated the so-called microsomal fraction which is formed from the endoplasmic reticulum when the cell is homogenized and fractionated by differential ultracentrifugation. Microsomal vesicles are thus fragments of the endoplasmic reticulum... 

Combination of Equations (9-88)-(9-91) gives what is called the Lamm differential ultracentrifuge equation ... 

Although this example shows that e.r. is not the sole site of metabolic degradation, this organelle is by far the most versatile. It can be separated from liver by differential ultracentrifugation and is similarly freed from the neigh-... 

Although this example shows that e.r, is not the sole site of metabolic degradation, this organelle is by far the most versatile. It can be separated from liver by differential ultracentrifugation and is similarly freed (Rothschild, 1961) from the neighbouring ribosomes which are sites of protein synthesis. During the course of much purification, the e,r, is broken up into spherules ( microsomes ) without loss of enzyme activity. These enzymes, which are numerous, are mainly oxidative, but a few of them perform reduaions, hydrolyses, and at least one synthesis (Fouts, 1962 ... 

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