Complex Macromolecules: The Five Types Of Proteins

Proteins are complex macromolecules that are formed by elements carbon, hydrogen, oxygen and nitrogen. Proteins composed of one or more polypeptide chains of amino acids. The main functions of proteins are to structure, support, protect, make movement, catalyst, transport and make hormones in human body. In the structural role, collagen and elastin provide support for connective tissue. Actin and myosin are proteins that involved in muscle contraction and movement. Haemoglobin is a protein that transports oxygen through the blood. For protection, there are immunoglobulins. Immunoglobins are glycoprotein molecules that are produced by plasma cells. It functions as antibodies. There are five types of immunoglobulins, which is IgG, IgA, IgM, IgD, and IgE. They are many different functions for each of the immunoglobulins.

Amino acids are the building blocks of proteins. All amino acids have the same basic structure but differ in their R-side chains. Each amino acid consists of an amino group (-NH3), a carboxyl group (-COOH) and a hydrogen atom (H). The amino and carboxyl groups are attached to a central alpha carbon together with a hydrogen atom and an R-side chain. There are currently known that over 170 amino acids occur in organisms but only 20 are commonly found in proteins. R groups determine the chemical properties of the amino acids. The simplest amino acids have hydrocarbons as side chains which are neutral and non-polar or hydrophobic. They are not soluble in water. Amino acids with a polar R group are neutral and polar or hydrophilic. They are more soluble in water. Polar side chains can be uncharged or carry a negative or positive