biological chemistry

Classification of Proteins Based on Structure and Function

protein classification

Classification of Proteins

Proteins are important macromolecules of the cells, formed by the polymerization of amino acids according to the sequence of genetic code in the mRNA. Proteins are the mode of expression of the genetic information. They perform a variety of duties in the cells such as they act as the structural components of cells, enzymes, hormones, pigments, storage proteins and some toxins in the cells. The proteins are classified into many categories based on different criterions.

Criterion for the classification of proteins:

Ø  Proteins are classified based on the following THREE criterions:

                             (I).     Classification based on STRUCTURE of Protein

                            (II).    Classification based on COMPOSITION of Protein

                           (III).    Classification based on FUNCTIONS of Proteins

(I). Classification of Proteins based on the Structure of Proteins

Ø  Based on the structure, proteins are classified into 3 groups.

(A).   Fibrous Proteins

(B).   Globular Proteins

(C).   Intermediate Proteins

(A). Fibrous Proteins

Ø  They are linear (long fibrous) in shape.

Ø  Secondary structure is the most important functional structure of fibrous proteins.

Ø  Usually, these proteins do not have tertiary structures.

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