Classification of proteins

You can divide proteins according to the form: you have globular proteins and fibrilar proteins.
  1. Fibre proteins - at least 10 x longer than broad. Example: nails, skin: keratine.
  2. Globular proteins - spherical in form, so length and broadness do not differ very much. examples: enzymes, antibodies, membrane proteins, hemoglobine, chlorophyl, etcetera.
This division has directly to do with the two most important functions of proteins:
  1. production of tissue (muscles, skin, bone, colagene, etc.)
  2. catalysing (controle of the reactions, transmission of nerve impulses, immuno protection)

The study of proteins is basic for understanding genetics.
In the lab at least is needed for such studies: purification and separation of proteins with techniques like chromatography and electrophoresis.

Considering the composition of protein molecules, we can divide proteins in: simple and complex.
  1. Simple proteins or homoproteins: - they are only composed of amino acids and nothing else. Examples: insuline, albumine, keratine, fibrinogene (occuring in blood plasm)
  2. Complex proteins or heteroproteins: - they are connected with non-protein structures, like the prostetic group.

Examples of group B:
  1. Chlorophyl, of who the prostetic group is Mg
  2. Hemoglobine, of who Heme + Fe is the prostetic group
  3. casein (in milk), of who the prostetic group is phosphate
  4. nucleic proteins: - mostly in the ribosomes, and of who the prostetic group is a ribonubleic acid (RNA) or (DNA)
  5. glycoproteins, of who the prostetic group is a saccharide; lipoproteins with lipides as a prostetic group.
  1. Complex proteins are divided according to their prostetic group.
  2. If the prostetic group has a certain color, we also can talk about chromoproteins.

About their fundamental function, the proteins are classified in structure proteins and enzymes:
  1. Structure proteins:
    belong to the cell structure and are building materials
  2. Enzymes:
    controle practically all chemical reactions in the cells.