Classify proteins according to its functions. Write notes on denaturation of protein

Classification of protein:

1.      Classification of protein based on size, shape and solubility.

a.      Simple protein: composed of only amino acid residues without any non protein substance.

                                                              i.      Fibrous protein: Collagen, Elastin, Keratin

                                                            ii.      Globular protein: Albumin, Globulin, Protamine, Histone.

b.      Conjugated protein:

                                                              i.      Nucleoprotein

                                                            ii.      Lipoprotein

                                                          iii.      Glycoprotein

                                                          iv.      Ferritin

                                                            v.      Carbonic anhydrase

                                                          vi.      Ceruloplasmin

                                                        vii.      Hemoglobin,myoglobin

c.       Derived protein

                                                              i.      Primary derived protein: Protean, Metaprotein

                                                            ii.      Secondary derived protein: Proteose, Peptone, Polypeptides, Peptides.

2.      Functional classification of protein:

a.      Structural protein

b.      Catalytic protein

c.       Transport protein

d.      Hormonal protein

e.      Gene regulatory protein

f.        Protective protein

g.      Receptor protein

h.      Contractile protein

3.      Nutritional classification of protein

a.      Complete protein: Egg albumin, Meat.

b.      Incomplete protein: Gelatin, Zein.

c.       Partially incomplete protein:

Denatured protein:

·        Proteins produced following loss of their native structural conformation due to the disruption of secondary, tertiary and quaternary structure, preserving the primary structure with alteration of physical, chemical and biological property.

·        No intra molecular change occur.

·        Usually it is irreversible process, but rarely it may be reversible.

·        It is done by:

o   Physical agent : heating, freezing, ultrasound, X-ray

o   Extreme P^H, strong acid, strong alkali & detergent

o   Organic solvent, heavy metals, trichloro acetic acid

o   High urea concentration

·        Alterations of protein that occur following denaturation:

o   Physical alteration

o   Chemical alteration

o   Biological alteration