Facts About Proteins

All biological organisms need proteins for their proper functioning. Proteins are involved in many biochemical reactions. Many proteins are enzymes - biological catalyzers which are directly involved in chemical transformations. Some are structural proteins such as those that are found in muscles and other tissues. Another set of proteins are regulatory substances known as hormones which are the body's chemical messengers that cause Here are some interesting facts about proteins and proteins structure.

Today there is a lot of talk and writing about nanoparticles and the revolution they are making in science and technology. It seems that nature started this nanotechnology thing many years ago. In fact proteins are nanoparticles (by definition a nanoparticle is any particle less than 100 nanometers). Understanding this definition is opening up new and exciting areas of research.

There are thousands of different proteins within each organism, but they are built from a repository of only 20 amino acids. These amino acids are sometimes called the building blocks of life, and they are constructed in the protein building factory of the cell - the ribosome.

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Proteins have levels of structure: primary, secondary, tertiary, and quaternary.

Primary structure: refers to the linear amino acid sequence of a protein structural chain or chains (see quaternary).

Secondary structure: these are regular sub-areas of the peptide chain which assume special configurations such as alpha helix and strands of beta sheet.

Tertiary structure: this is referred to as the 3-D structure of a protein molecule. It is the spatial arrangement of the secondary structures. Tertiary structure refers to folding of the peptide chain.

Quaternary structure: there are proteins made of various polypeptide chains. These individual polypeptide chains assemble in a super structure with higher complexity. The function of these complex structures depends of the correct assembly of the subunits.

Hemoglobin is an excellent example of a quaternary structure. The hemoglobin in blood is the molecule that carries oxygen through the body. It contains two α and two β subunits arranged with a quaternary structure in the form, α2β2.

The complexity of proteins increase as they interact with other chemical components, mainly carbohydrates, to form what are known as glycoproteins. These proteins are formed after proteins synthesis, thus they are called post-translational modifications (translation is the process by which DNA is translated into protein structure). There are many important proteins that are glycoproteins such as those found on the surface of erythrocytes (the red blood cells). Actually, these glycoproteins determine the most common blood groups (A, B, and O).

There are also lipoproteins - proteins linked (non covalent bonds) to lipids. Lipoproteins are mainly involved in storing and moving lipids and cholesterol.

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