ABSTRACT
Proteins are usually considered the most important of all the known substances present in living matter, without which life would be impossible on our planet. The proteins are one of the three principal organic constituents of living organisms (the other two are fats and carbohydrates), but in importance and diversity of their biological functions they stand alone. Proteins represent nearly one-half of the body’s dry matter (about 70% of the body is water). Of the total body pro tein, more than a third is found in the muscles. These are the myosin fibers, which are the funda mental contractile elements in muscular movement. The bones and cartilages account for another 20%, where the protein collagen contributes to the structural stability of the skeleton. The skin has about 10% of the body protein, the keratin serving to protect the interior tissues against attack from the external environment.
