Protease What Are

Proteases also known as peptidases are enzymes that catalyse the hydrolysis of peptide bonds.

Proteolysis is an essential process for many biological functions including digestion, blood coagulation, hormone processing and apoptosis (programmed cell death)

Proteases are extremely diverse and can be classified according to their catalytic mechanisms, substrate specificities, and structures. The three major classes proteases are:

* Serine proteases, which use a serine residue in their active site to attack the peptide bond. Serine proteases include trypsin, chymotrypsin, and elastase.

* Cysteine proteases, which use a cysteine residue in their active site to attack the peptide bond. Cysteine proteases include papain, cathepsin B, and caspase-3.

* Aspartic proteases, which use two aspartic acid residues in their active site to attack the peptide bond. Aspartic proteases include pepsin, cathepsin D, and renin.

Proteases are also classified according to their substrate specificities. Some proteases are highly specific for particular sequences of amino acids, while others are more promiscuous. The substrate specificity of a protease is determined by the structure of its active site.

Proteases play a vital role in many biological processes. In digestion, proteases break down proteins into smaller peptides and amino acids that can be absorbed by the body. In blood coagulation, proteases activate the clotting factors that lead to the formation of a blood clot. In hormone processing, proteases cleave prohormones into their active forms. In apoptosis, proteases break down the cell's structural proteins, leading to cell death.

Proteases are also involved in a number of diseases. For example, the excessive activity of proteases can lead to inflammation and tissue destruction. Protease inhibitors are drugs that can block the activity of proteases and are used to treat a variety of diseases, including emphysema, arthritis, and cancer.