CHAPTER 19: Unit 1. Amino Acids and Proteins Definition, Types and Functions

Amino Acids are organic carboxylic acids that have amino group (-NH₂). Amino acids are very important components of proteins production in human’s body.

Proteins are very important chemical compounds in forming muscles, cartilages, hair and nails in humans. Horns, wools and silk are made of proteins in animals.

Proteins can function as hormones and enzymes that regulate in the cellular metabolism as well as in the digestion.

Proteins are used in transporting oxygen in the blood and in the muscles. Such proteins are called hemoglobin and myoglobin.

Example of an amino acid is given below:

Reference: http://www.nutrientsreview.com/proteins/amino-acids            https://en.wikipedia.org/wiki/Protein_(nutrient)

An amino acid is shown above is made of organic carboxylic acid with an amino group attached to second carbonof the carboxylic acid and a side chain R connected to the second carbon atom as well.Depending on side chain R, one can differentiate between the following types and functions of amino acids:

Reference: https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_General_Biology_(OpenStax)/1%3A_The_Chemistry_of_Life/3%3A_Biological_Macromolecules/3.4%3A_Proteins

Reference: https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_General_Biology_(OpenStax)/1%3A_The_Chemistry_of_Life/3%3A_Biological_Macromolecules/3.4%3A_Proteins

The videos below illustrate the amino acids types and functions:

Proteins are condensation of amino acids through the formation of peptide bonds.

Reference: http://www.web-books.com/MoBio/Free/Ch2B.htm

The second carbon of the amino acid is designated with the symbol α and the third carbon atom is designated with the symbol β and the following carbons atoms are designated with γ δ and ε etc.When two amines are reacting together, they form a dipeptide in which the oxygen of first carboxylic acid of the first amino acid is reacting with 2 H atoms of the second amino group of the second amino acid. Water is produced as byproduct.The α carbon of the first amino acid is called N – terminus.The α carbon of the second amino acid is called C – terminus

Peptides Naming:

Reference: https://slideplayer.com/slide/8063783/

The order of the amino acids in the peptide is written as the sequence of three – letter or one -letter abbreviation.

The videos below illustrate the naming of peptides: