Introduction of Proteins as biopolymer

The sources of proteins which are contained in living organism

When speaking about polymer, the first thing that comes out on our mind is the rubber. Well, it is not incorrect completely, but the definition of polymer is clear which is related to the monomer itself – you could find it in “general understanding of polymer–. Interestingly, most of the polymers itself are found in the living organisms and one of those is Protein.

Protein is one of the polymer which can be found in the body of living things. Because of the location lies within on living things, this polymer is classified as biopolymer which means a biological polymer. Actually, the word protein(s) with “s” means various. So, the all proteins are a polymer that contains alpha-amino acids meaning as the monomer. However, the difference between one protein to another protein depends only in two things which are the three-dimensional molecular structure and the functions of the proteins themselves for the organisms.

In living organisms, proteins give lot of benevolence. Proteins can become the protectors to several mammals and sometimes when they act as enzyme, the protein becomes one of the most efficient catalysts in operating the bio-chemical reaction. On the other hand, proteins are demanded for people who get wound in regenerating the damaged cells. Now, let’s analyze the structure of the proteins and what makes the proteins are different each other’s.

Firstly, the monomers of the proteins are the alpha-amino acids which has two configurations. They are the L and D –alpha-amino acids. What any the distinguishing features of these two amino acids? Based on the illustrations posted below that the structure of amino acids clearly explained about the location of aminos. On the L-amino acid, the location is at 6 o’clock while the D-amino acid is at 3 o’clock. This is the explanation of differences mentioned previously about the three-dimensional molecular structure.

Structure of amino acids taken from MacGregor's

Next is the chemical compositions of proteins. Proteins have common formula which is H2N-CHR-COOH, and this formula is the monomers for the proteins. So, if we plan to synthesize the protein, the first thing we have to do is understanding of this monomer. In total there are nineteen different proteins and they are differed based on their “R’s” (look at the illustration again, the symbol of R is located on left side or 9 o’clock). The lists are:

• Glycine
• Alanine
• Valine
• Leucine
• Isoleucine
• Serine
• Threonine
• Aspartic acid
• Asparagine
• Glutamic acid
• Glutamine
• Arginine
• Lysine
• Hydroxylysine
• Methionine
• Cysteine
• Cystine
• Histidine
• Tryptophan
• Phenylalanine
• Tyrosine
• Proline
• 4-Hydroxyproline

For hydroxylysine, cysteine, and 4-hyrosyproline are created in incorporating the preceding acid into protein by chemical reaction.

So, these twenty-four of proteins differ to each other based on the R’s side and three-dimensional molecular structure. The question is how they are bonded? What is the name of the bonding? Can you guess it? Find the answer on the next article in www.aeglephysics.com

References
[1] E. A. MacGregor, "Biopolymers," in Encyclopedia of Physical Science and Technology, San Diego, Academic Press, 2002, pp. 207-245.
[2] Image is downloaded from www.meanshealth.com