Box 11-2 What Is Isoelectric Focusing

The stained gel is shown at the bottom of the figure. A spectrophotometric scan of the dye peaks is shown on the graph, and a profile of measured pH is also plotted. Each dark band of stained protein gives an absorbance peak. 

Living cells also have isoelectric points and can be separated from one another by isoelectric focusing. 

Isoelectric focusing of a mixture of proteins (1) soybean trypsin inhibitor (2) p-lactoglobulin A (3) p-lactoglobulln B (4) ovotransferrin (5) horse myoglobin (6) whale myoglobin (7) cytochrome c. [Bio-Rad Laboratories, Hercules, CA.] 

Consider the titration of 50.0 mL of0.050 0 M malonic acid with 0.100 M NaOH. 

Both equations are always true and either can be used, depending on which set of concentrations you happen to know. 

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