James Batcheller Sumner – discoverer of protein nature of enzymes

James Batcheller Sumner – discoverer of protein nature of enzymes

All Enzymes Are Proteins but Not All Proteins Are Enzymes
James Batcheller Sumner – discoverer of protein nature of enzymes

Biography & contributions

James Batcheller Sumner was born on November 19, 1887 – died on August 12, 1955. Sumner was an American biochemist and Nobel laureate. Sumner crystallized and isolated the enzymes and discovered protein nature of enzymes.Sumner crystallized some of the enzymes like Urease in the year of 1926, another enzyme called Catalase crystallized in the year of 1937.

Sumner was the receiver of various famous medals and awards like Guggenheim Fellowship in the year of 1937, Scheele Award in the year of 1937, Nobel Prize for crystallization of enzymes in the year of 1946.


Enzymes are large biological molecules accountable for the thousands of chemical interconversions that sustain life. These are usually very specific as to which reactions they catalyze and the substrates that are involved in these reactions.They are highly selective catalysts, greatly accelerating both the rate and specificity of metabolic reactions, from the digestion of food to the synthesis of DNA.

Enzymes are known to catalyze about 4,000 biochemical reactions.Activators and Inhibitors are key factors that effect enzymes activity.Like all catalysts, enzymes work by lowering the activation energy for a reaction, thus dramatically increasing the rate of the reaction.Enzymes are in general globular proteins and range from just 62 amino acid residues in size.


Catalase is an enzyme responsible for the degradation of hydrogen peroxide. It is a protective enzyme present in nearly all animal cells.

Mechanism of catalase

The reaction of catalase occurs in two steps. A molecule of hydrogen peroxide oxidizes the heme to an oxyferryl species. A porphyrin cation radical is generated when one oxidation equivalent is removed from iron and one from the poryphyrin ring. A second hydrogen peroxide molecule acts as a reducing agent to regenerate the resting state enzyme, producing a molecule of oxygen and water.

Catalase composition

Catalase is a tetramer consisting of four identical, tetrahedrally arranged subunits. Each 60 kDa subunit contains a heme group and NADPH in its active center.

Catalase inhibitors

Catalase applications

Catalase applications in food industry

Catalase is used in food industry to remove hydrogen peroxide from milk which is used to make cheese. It is also applied to food packing, in order to prevent the food from being oxidized.

Catalase applications in textile industry

In textile industry, catalase is used to remove hydrogen peroxide from the textile fabrics, and thus ensure that the finish products don’t contain peroxides.

Catalase applications in optical equipments

It is also used to clean contact lenses.

Catalase applications in cosmetics industry

Catalase also used in beauty industry. Catalase and hydrogen peroxide is added to some facial cares to increase the amount of oxygen in the cells of the upper epidermis.

Catalase applications in laboratories

Catalase is also often used in the laboratory as a tool that is used to learn about how enzymes affect reaction rate.

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