Proteases

Proteins are broken down by enzymes called proteases or proteinases, which break down the peptide chains. These enzymes are required for so many biological functions, including protein turnover, digestion, immune responses, blood clotting, and cell signaling. As ubiquitous molecules found in every organism, from viruses and bacteria to human, proteases are truly universal. Thousands of protease types have been identified, each with unique functions in different species. Their precise ability to degrade or modify proteins has made proteases indispensable in both research and industry. Creative Enzymes is honored to offer a wide range of proteases with multiple functions for various applications in industry and research. Explore with us the catalytic mechanism of proteases, the diversity and variety of applications, and find the products you need!

Enzymatic Mechanism of Proteases

Proteases hydrolyze the peptide chains that link amino acids. The general mechanism of protease activity involves nucleophilic attack on the carbonyl carbon of the peptide bond, resulting in cleavage of the bond and release of the amino acid fragments. Proteases are typically classified according to their catalytic activity as serine proteases, cysteine proteases, aspartic proteases, and metalloproteases.

• Serine Proteases: These enzymes use a serine residue in their active site to initiate the nucleophilic attack on the peptide bond. The catalytic triad of serine, histidine, and aspartate is critical for this reaction. Common examples include trypsin, chymotrypsin, and thrombin.
• Cysteine Proteases: In this group, a cysteine residue acts as a nucleophile, supported by a histidine residue as a general base. Papain and caspases are prominent cysteine proteases.
• Aspartic Proteases: Aspartic proteases have two aspartic acid residues that activate a water molecule that then attacks the peptide bond. Examples include HIV protease and pepsin.
• Metalloproteases: These proteases require a metal ion, usually zinc, to facilitate hydrolysis of the peptide bond. The metal ion coordinates with a water molecule to initiate the attack on the peptide bond. Matrix metalloproteases (MMPs) and thermolysin are typical metalloproteases.

To prevent uncontrolled protein degradation, protease activity is carefully controlled. This regulation is achieved through the activation of zymogens (inactive forms of enzymes) or through the action of protease inhibitors, which bind to proteases and block their enzymatic activity.

Fig. 1: Catalytic Mechanisms of Mammalian Proteases. The five major catalytic classes of proteases use two fundamentally different catalytic mechanisms to stabilize the tetrahedral intermediate. In serine, cysteine, and threonine proteases, the nucleophile of the catalytic site is part of an amino acid (covalent catalysis), whereas in metalloproteinases and aspartic proteases, the nucleophile is an activated water molecule (non-covalent catalysis). In covalent catalysis, histidines usually act as bases, whereas in non-covalent catalysis, Asp or Glu residues and zinc (metalloproteinases) act as acids and bases. Another difference between the two groups is the formation of the reaction products from the tetrahedral intermediate, which for cysteine and serine proteases requires an additional intermediate step (acyl enzyme intermediate) (Turk, 2006).

Proteases with Different Recognition Sites Selection Guide

Biodiversity of Proteases

Proteases are highly diverse enzymes found in animals, plants, fungi, bacteria, archaea and viruses. This diversity highlights their many essential roles in biological systems.

• Animal Proteases: In animals, proteases play crucial roles in digestion (e.g., trypsin and pepsin), immune system responses (e.g., caspases that regulate cell death), and blood clotting (e.g., thrombin). This diversity enables animals to finely control these vital processes.
• Plant Proteases: In plants, proteases support protein recycling, defense, and programmed cell death. Cysteine proteases, like papain from papaya, are especially important for processes like seed germination and pathogen resistance.
• Microbial Proteases: Microorganisms produce proteases to break down proteins in their environment and provide them with nutrients. Some microbial proteases, such as those from Bacillus species, are widely used in industry because of their ability to withstand extreme conditions. Fungi also produce proteases that aid in food production, such as in the cheese making process.
• Viral Proteases: Many viruses encode proteases that are essential for their life cycle. For example, HIV protease processes viral polyproteins into functional proteins, an essential step targeted by antiretroviral drugs.

Protease With Different Properties Selection Guide

Applications in Industry and Research of Proteases

Proteases are widely used in industry and research for their ability to efficiently degrade proteins under controlled conditions.

Research

In scientific research, proteases are used for a variety of purposes. They are essential in cell culture, where enzymes such as trypsin help to separate cells. In mass spectrometry-based proteomics, proteases cleave proteins into peptides for structural analysis. They are also important in studies of enzyme function, protein interactions, and drug screening.

Pharmaceuticals

Proteases play a role in the production of therapeutic proteins and peptides. For example, they are used in insulin production to remove unwanted peptide chains. Researchers are also studying proteases for cancer treatment, as abnormal protease activity is often associated with tumor growth.

Food Industry

Proteases improve the texture, flavor and digestibility of various foods. For example, in cheese making, rennet, which contains the protease chymosin, helps to coagulate milk proteins. Proteases also tenderize meat and create protein hydrolysates that add flavor to soups and sauces.

Detergent Industry

Proteases are essential in detergents to help remove protein-based stains such as blood and food. Bacterial proteases from Bacillus species are particularly useful because of their stability at high temperatures and alkaline pH levels.

Bioremediation

In bioremediation, proteases help break down protein-based contaminants found in wastewater and industrial waste. They're particularly useful in treating waste from the animal and food industries, where there's a lot of protein material to deal with.

Fig. 2: Applications of protease enzyme in various industries/sectors (Solanki et al., 2021).

Proteases for Industrial Use Selection Guide

In short, proteases are an important group of enzymes that play a crucial role in various biological processes. They're valuable not only in natural biological systems, but also in many industries. Their wide range of applications—from food production to pharmaceuticals to bioremediation—shows how versatile and important they are in today's science and technology.

Creative Enzymes offers a wide range of protease products. These proteases have different properties, including different sources, activities, and specificities. Whether you need native or recombinant enzymes, or enzymes for special conditions, we've got you covered. If you have any questions, please contact us today!