Saturday, December 7, 2013

Amino Acids and Important Facts

An amino acid (AA) is a small organic compound with an amine group(NH3), a carboxyl group (COOH) (the acid), and one or more atoms called an “R group.” In most amino acids, all three groups are attached to the same carbon atom. Amine group acts like a base, tends to be positive. Carboxyl group acts like an acid, tends to be negative. Side chain “R” group is variable, from 1 to 20. During protein synthesis, the amine group of one amino acid becomes bonded to the carboxyl group of the next to make a polypeptide chain.

Amino acids contain carbon (C), hydrogen (H), oxygen (O), nitrogen (N) and sulfur (S)
There are 20 different kinds of amino acids (AA)

Amino acids are divided into two groups- 1. Essential AA
                                                                    2. Non-essential AA
1. An essential amino acid or indispensable amino acid is an amino acid that cannot be synthesized by the organism (usually referring to humans), and therefore must be supplied in the diet.
2. A non-essential amino acid is an amino acid that can be synthesized by the organism (usually referring to humans).So there is no deficiency of this AA in the body if they are not supplied in the diet.
Protein synthesis involves covalently bonding amino acids into a chain. The bond that forms between two amino acids is called a peptide bond. Enzymes repeat this bonding process hundreds or thousands of times, so a long chain of amino acids (a polypeptide) forms.


 Important Fact

1. Most microorganisms and plants can biosynthesize all 20 standard amino acids, while animals (including humans) must obtain some of the amino acids from the diet. The amino acids that an organism cannot synthesize on its own are referred to as essential amino acids
2. In animals, amino acids are obtained through the consumption of foods containing protein. Ingested proteins are then broken down into amino acids through digestion, which typically involves denaturation of the protein through exposure to acid and hydrolysis by enzymes called proteases. Some ingested amino acids are used for protein biosynthesis, while others are converted to glucose through gluconeogenesis, or fed into the citric acid cycle. This use of protein as a fuel is particularly important under starvation conditions as it allows the body's own proteins to be used to support life, particularly those found in muscle. Amino acids are also an important dietary source of nitrogen.