The Characteristics of Enzymes in the Body - Essay Example

1. Explain in full the characteristics of enzymes in the body Enzymes are organic compounds that catalyze biochemical reactions (Stoker 2006). As they are catalysts, they are not consumed in the reaction but instead, facilitate a faster reaction rate. Enzymes in the body are mostly globular proteins or conjugated proteins, while some are simple proteins composed of simple amino-acid chains (Stoker 2006). While almost all the known enzymes are proteins, enzymes such as RNase made of ribonucleic acids have also been discovered.

Important characteristics of enzymes are discussed as follows: Specificity: Enzymes are produced by living cells only (Wright 2000). They are very specific to the substrate and one particular enzyme will only catalyze one specific reaction. Enzymes have a fixed structure and shape that is vital for its functionality. Changes in the structure and shape of an enzyme will result in loss of enzymatic activity, as the active site of that enzyme will be altered. Specificity is the most important characteristic of enzymes.

Enzymes are not only specific to the type of reaction they catalyze but also to the particular compounds that are involved in the reaction (Seager & Slabaugh 2010). For instance, urease catalyzes the hydrolysis of urea only. This is called absolute specificity of the enzyme. Some enzymes also demonstrate relative specificity, i.e. the catalysis of structurally similar substrates such as lipids, proteins etc, whose hydrolysis is catalyzed by lipases and proteases, respectively (Seager & Slabaugh 2010).

Some enzymes also display stereochemical specificity. Enzymes that possess this specificity catalyze specific enantiomers, for instance, the enzyme D-amino acid oxidase will catalyze only D-amino acids and not L-amino acids (Seager & Slabaugh 2010). Denaturation: Enzymes undergo denaturation upon slight variations in temperature and pH, as well as in the presence of chemicals that are protein denaturants (Stoker 2006). Enzymes work best at a particular optimum temperature and pH specific to that enzyme.

Denaturation of an enzyme occurs when the shape of the enzyme is altered by changes in temperature and pH, both of which affect the protein structure of the enzyme. Denaturation results in the deactivation or loss of enzymatic function of an enzyme. Above and below the optimum temperature and pH, the activity of the enzyme either slows down or comes to a halt. Inhibition: Certain chemicals called inhibitors also affect the functioning of an enzyme. Inhibitors deactivate enzymes in several ways.

They may bind to the active site of an enzyme and alter its shape, resulting in an inhibition of its catalytic activity (Wright 2000). Substrate & Product Concentration: The catalytic activity of enzymes is not only affected by the pH and temperature, but also the concentration of the substrate and the product (Seager & Slabaugh 2010). As the concentration of the substrate increases, the enzymatic activity also increases up to certain substrate concentration. On the other hand, as the concentration of the product increases, the enzymatic activity decreases.

Enzymes in the body follow Michaelis–Menten kinetics. Regulation: Another important characteristic of enzymes is that their catalytic activities can be regulated. The rate of any given reaction at a particular time is controlled by the cell by regulating the enzyme that catalyzes that particular reaction (Seager & Slabaugh 2010). Enzymes are thus strictly regulated by the cell. References Seager, SL & Slabaugh, MR 2010, Chemistry for today: General, organic and biochemistry, California, Cengage Learning Stoker, SH 2006, General, organic, and biological chemistry, Massachusetts, Cengage Learning Wright, D 2000, Human physiology and health, Oxford, Heinemann Educational Publishers