What are the different classifications of proteins?
Answers
Answer:
On the basis of shape
Fibrous protein(Scleroprotein): We can find these proteins in animals and are insoluble in water. Fibrous proteins are resistant to proteolytic enzymes and are coiled and exist in threadlike structures to form fibres. e.g. collagen, actin, and myosin, keratin in hair, claws, feathers, etc.
Globular proteins: These proteins, unlike fibrous proteins are soluble in water. They are made up of polypeptides that are coiled about themselves to form oval or spherical molecules e.g. albumin, insulin, and hormones like oxytocin, etc.
On the basis of Constitution
Simple proteins: These proteins are made up of amino acids only. e.g. albumins, globulins, prolamins, etc.
Conjugated proteins: These are complex proteins that are combined with the characteristic of non–amino acid substance called as a prosthetic group. These are of following types:–
Nucleoproteins: Combination of protein and nucleic acid
Mucoproteins: Combination of proteins and carbohydrates (>4%)
Glycoproteins: Combination of proteins and carbohydrates(<4%)
Chromoproteins: Combination of proteins and coloured pigments.
Lipoproteins: Combination of proteins and lipids.
Metalloprotein: Combination of proteins and metal ions.
Phosphoprotein: Combination of proteins and phosphate group.
Derived proteins: When proteins are hydrolyzed by acids, alkalies or enzymes, the degradation products obtained from them are called derived proteins.
On the basis of nature of Molecules
Acidic proteins: They exist as anion and contain acidic amino acids. e.g. blood groups.
Basic proteins: They exist as cations and are rich in basic amino acids e.g. lysine, arginine etc.
Explanation: