Nature of Proteins

CCA! Volume 5

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Nature of Proteins

Effect of pH on solubility, denaturing proteins, hydrolysis in strong base, binding to coomassie blue, dying wool and cotton, gel filtration column, reaction of ninhydrin with amino acids and precipitating protein with ammonium sulfate are demonstrated.

Effect of pH on the solubility of Casein

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3 Slides

A basic solution of casein is titrated with 2M HCl.

Denaturing Proteins

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3 movies

Egg white proteins are denatured by acid, lead solution, and heat.

Hydrolysis of Protein in Strong Base

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2 movies

Concentrated sodium hydroxide causes wool and hair to dissolve.

Binding Protein to Coomassie Blue

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46 seconds

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Coomassie blue binds to proteins forming a blue color. As more protein is added, the solution becomes a deeper blue color.

Dyeing Wool and Cotton

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64 seconds

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9 Slides

Martius yellow dye colors wool but not cotton.

Gel Filtration Column

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80 seconds

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Blue dextran, hemoglobin and riboflavin are passed through gel filtration columns.

Reaction of Ninhydrin with Amino Acids

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74 seconds

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Ninhydrin reacts with amino acids to produce a violet compound.

Precipitating Protein with Ammonium Sulfate

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71 seconds

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5 Slides

Different egg white proteins are precipitated, depending on the amount of ammonium sulfate added to the mixture.

Copyright © 2001 Division of Chemical Education, Inc., American Chemical Society. All rights reserved.