Enzymes

Enzymes are biological molecules (typically proteins) that significantly speed up the rate of virtually all of the chemical reactions that take place within cells. They are vital for life and serve a wide range of important functions in the body, such as aiding in digestion and metabolism.

Structure

Most enzymes are proteins, although a few are catalytic RNA molecules. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life.

Function

Enzymes play a critical role in the body. They are necessary for digestion, where they break down food into its nutrient pieces. Enzymes also help out with metabolism, where they speed up chemical reactions to help our body live and function. Enzymes also assist in the process of DNA replication and transcription, helping our body to copy DNA when it divides.

Classification and Nomenclature

Enzymes are classified into several broad categories, such as hydrolytic, oxidizing, reducing, etc. depending on the type of reaction they control. The International Union of Biochemistry (IUB) has developed a nomenclature for enzymes, the EC numbers; each enzyme is described by a sequence of four numbers preceded by "EC".

Enzyme Deficiency

Enzyme deficiencies can lead to a wide range of diseases. For example, phenylketonuria and alkaptonuria are genetic disorders caused by the deficiency of the enzymes phenylalanine hydroxylase and homogentisate 1,2-dioxygenase, respectively.

See Also

• Proteins
• Metabolism
• DNA replication
• Transcription
• Phenylketonuria
• Alkaptonuria

Enzymes Resources
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