Classification of proteins
You can divide proteins according to the form: you have globular proteins and fibrilar proteins.
- Fibre proteins - at least 10 x longer than broad. Example: nails, skin: keratine.
- 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:
- production of tissue (muscles, skin, bone, colagene, etc.)
- 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.
- Simple proteins or homoproteins: - they are only composed of amino acids and nothing else. Examples: insuline, albumine, keratine, fibrinogene (occuring in blood plasm)
- Complex proteins or heteroproteins: - they are connected with non-protein structures, like the prostetic group.
Examples of group B:
- Chlorophyl, of who the prostetic group is Mg
- Hemoglobine, of who Heme + Fe is the prostetic group
- casein (in milk), of who the prostetic group is phosphate
- nucleic proteins: - mostly in the ribosomes, and of who the prostetic group is a ribonubleic acid (RNA) or (DNA)
- glycoproteins, of who the prostetic group is a saccharide; lipoproteins with lipides as a prostetic group.
N.B.
- Complex proteins are divided according to their prostetic group.
- 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:
- Structure proteins:
belong to the cell structure and are building materials
- Enzymes:
controle practically all chemical reactions in the cells.