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Protein precipitation is widely used in downstream processing of biological products in order to concentrate proteins and purify them from various contaminants. For example, in the biotechnology industry protein precipitation is used to eliminate contaminants commonly contained in blood. [1]
Protein crystallization is the process of formation of a regular array of individual protein molecules stabilized by crystal contacts. If the crystal is sufficiently ordered, it will diffract . Some proteins naturally form crystalline arrays, like aquaporin in the lens of the eye.
Independently floating casein molecules attract one another, forming "curdles" that float in a translucent whey. [1] At warmer temperatures, the clumping reaction occurs more quickly than at colder temperature. [1] Curdling occurs naturally if cows' milk is left open in a warm environment to air for a few days. [citation needed]
Variety of microbiological samples. A laboratory specimen is sometimes a biological specimen of a medical patient's tissue, fluids, or other samples used for laboratory analysis to assist in differential diagnosis or staging of a disease process. These specimens are often the most reliable method of diagnosis, depending on the ailment.
Ammonium sulfate is an inorganic salt with a high solubility that disassociates into ammonium (NH + 4) and sulfate (SO 2− 4) in aqueous solutions. [1] Ammonium sulfate is especially useful as a precipitant because it is highly soluble, stabilizes protein structure, has a relatively low density, is readily available, and is relatively inexpensive.
Generally, the cell sample is stored in a suspension which is: Buffered—neutral pH, preventing damage to the structure of proteins including enzymes (which could affect ionic bonds) Isotonic (of equal water potential)—this prevents water gain or loss by the organelles; Cool—reducing the overall activity of enzyme released later in the ...
Loading aids; most PAGE systems are loaded from the top into wells within the gel. To ensure that the sample sinks to the bottom of the gel, sample buffer is supplemented with additives that increase the density of the sample. These additives should be non-ionic and non-reactive towards proteins to avoid interfering with electrophoresis.
The test is based on the observation that a suitable amount of sulfuric acid added to the milk will dissolve proteins and other components, except the fat. Heating and centrifuging cause the fat to separate and float to the top, in a layer free of bubbles. The amount of fat in the milk can then be estimated from the volume of that layer.