How do Enzymes Work?

Enzymes serve as biological catalysts (biocatalysts). They accelerate chemical reactions by acting on molecules, known as substrates, and convert them into different molecules, referred to as products. Almost all metabolic processes in a cell require enzyme catalysis to occur at rates that can sustain life. Various metabolic pathways depend on enzymes to catalyze individual steps.

Similar to all catalysts, enzymes increase the rate of a reaction by reducing its activation energy. Some enzymes can speed up the conversion of substrate to product by millions of times. An extreme example is orotidine 5′-phosphate decarboxylase, which enables a reaction that would ordinarily take millions of years to happen in just milliseconds.

What are the Various Types of Enzymes?

Enzymes are classified into six different types based on the tasks they perform at the molecular level. Here are the six types:

1. Hydrolases – These enzymes break chemical bonds by adding water. There are over 200 different types of hydrolases.
2. Oxidoreductases – They catalyze oxidation and reduction reactions.
3. Transferases – They transfer functional groups from a donor molecule to an acceptor molecule.
4. Isomerases – These enzymes induce structural changes within a molecule. There are four different sub-categories of isomerases.
5. Ligases – DNA ligase, which catalyzes the ligation or repair of breaks in DNA.
6. Lyases – Also known as synthase enzymes.

What are Some Examples of Digestive Enzymes?

Here are five examples of digestive enzymes:

1. Amylase – This enzyme breaks down large starch molecules. It is produced in the salivary glands.
2. Pepsin – It helps in breaking down proteins and is produced in the stomach.
3. Trypsin – This enzyme also breaks down proteins and is produced in the pancreas.
4. Pancreatic lipase – It helps in breaking down fats and is produced in the pancreas.
5. Ribonuclease and deoxyribonuclease – These enzymes help in breaking down DNA and RNA. They are also produced in the pancreas.

How Many Enzymes are found in Human Cells?

Approximately 1300 distinct enzymes can be found in human cells.

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