Understanding Proteins

Proteins are amazing, versatile and vital cellular machines, without them life would not exist. Protein machinery comes in many forms: Enzymes, antibodies, transport vehicles, cellular pumps, oxygen carriers, tendons and ligaments, scars, the cores of bones and teeth, the filaments of hair and the materials of nails.

In fact, all cells of the body are partly composed of protein that constantly requires replacement. Carbohydrates and fats contain no nitrogen or sulphur, two essential elements in all proteins, whereas fat in the body can be derived from dietary carbohydrates and carbohydrates from proteins. The proteins of the body are dependent for their formation and maintenance on the proteins of the diet.

The major difference between proteins, carbohydrates and fats is the nitrogen or amino groups. A protein is a strand of individual amino acids of some twenty different kinds occurring in nature. These 20 amino acids resemble the 26 letters of the alphabet, since each can be arranged in sequences to form an infinite number of proteins and sentences respectively. It is the proteins that give each species its specific genetic and immunological characteristics.

The human body can make most of the amino acids for itself but there are nine amino acids which the adult human cannot manufacture from it's own materials and these essential amino acids must be supplied by the proteins of the diet.

The Nine Essential Amino Acids

• histidine
• isoleucine
• leucine
• lysine
• methionine
• phenylalanine
• threonine
• tryptophan
• valine

The Eleven Non Essential Amino Acids

• alanine
• arginine
• aspartic acid
• cysteine
• cystine
• glutamic acid
• glutamine
• glycine
• proline
• serine