1. Simple proteins

These are proteins that consist essentially of amino acid residue and no other compounde.g. histone and proteimens

2. Conjugated proteins

These are proteins which are linked with other compound. The non-proteinous compounds to which the proteins are attached are refered to as prosthetic groups usually a metal or a small organic molecule

• Nucleo proteins

These are proteins combine with nuclei acid (DNA or RNA) there are common in cells and be formed from the association of histone plus the nuclei acid or protamen plus nuclei acid

• Chromoproteins

These are proteins combine with colored pigments (chromophores) or colored compound. They are all soluable e.g. haemoglobin, myoglobin, cytochrome.

• Metaloproteins

These are proteins combine with metals e.g. carbonic which is an enzyme having zinc as the prosthetic group. It catalysis the breakdown of carbonic acid into h₂o and co₂

• Lipoproteins

These are proteins combine with lipids. They are common in the blood plasma, plasma membrane and brain

3. Globular proteins

These are soluable proteins of the boddy. They include plasma proteins such as globulin and intercellular as well as intracellular hormones and enzymes. Globular proteins usually have a tertiary structure

4. Fribrous

All structural material of the body are made up of fibrous proteins. They are insoluable and consist of parallel polypeptide chains e.g. keratin, myosin

Functions of Proteins

1. Structural functions

-Proteins are the components of kenetic tissue, bones, tendons and cartilage e.g. collagen

-Keratin is the component of the skin, nails, horn, feathers and the hairs

-The viral protein coat wraps up is nucleic acid of viruses

2. Enzymatic function

-Trypsin catalysis the hydrolysis of protein

-Ribulose biphosphate carboxylase catalysis the carboxlation (addition of co2) of ribulose in diphosphate photosynthesis

-Glutamine synthesis catalysis the synthesis of the amino acid, glutamine form glutamic acid and ammonia

3. Hormonal function

-Insulin and glucagon help to regulate glucose metabolism.

-ACTH (Adreno corticotrophic hormone) stimulated the growth and activity of the andrena cortex.

4. Respiratory function

-Aaemoglutin transport o₂ in the vetabrate blood.

-Myoglobin store oxygen in the muscle.

5. Transport function

-Serom albumin transport fatty acid and the lipid in the blood

6. Protective function

-Anti bodies form complexes which foreign particles

-Fibrinogen forms fibrin in the blood clotting

-Thrombin is involved in blood clotting organisms.

7. Contractile function

-Myosin helps in moving filaments in myofibrils of muscles

-Actin is the stationary filament in myofibrils of muscles

8. Storage function

-Ovalbumin is stored in egg white

-Caesin is the milk protein

1. Toxin function

-Snake venoms are enzymes

-Diphtheria toxins are made by Diphtheria bacteria