Subtilisin laundry

In order to prove enzyme engineering feasibility, it was important to develop a model system. One of the prime considerations for any model would be the commercial potential of the model. Table I lists the major commercial enzymes and the market size in US dollars (5). The alkaline proteases (subtilisins) are clearly the major single class of enzymes in commercial use today, representing 25% of the total enzyme market of 600 million. The primary use of subtilisins is as additives in laundry detergents to aid in the removal of proteinaceous stains from cloth. 

MW 27,500) with no cofactors or metal ions reqnirement for its function, it displays Michaelis-Menten kinetics and it is secreted in large amounts by a wide variety of Bacillus species. Subtilisin is also among the most important industrial enzymes due to its use in laundry detergents. Protein engineering strategies for subtilisin have focused on a number of aspects, namely catalysis, substrate specificity, thermal and oxidative stability and pH profile. We will describe briefly each of these aspects. 

An example of this kind of work involves the enzyme subtilisin, frequently used as an additive in laundry detergents because it attacks the proteins that soil clothing. The problem, however, is that subtilisin is easily destroyed by bleaches with which a detergent is often used. Research showed that subtilisin is sensitive to bleach because a single amino acid in its primary structure—a methionine at position 22—is destroyed by bleach. By replacing this methionine with an amino acid that is not sensitive to attack by bleach, then, researchers were able to synthesize a new form of subtilisin that did not degrade in the presence of bleach for use in laundry detergents. 

World War II spurred much advancement in the production of penicillin, particularly the advent of submerged fermentation processes. This new technique was soon adapted to the large-scale production of bacterial proteases. The first modern detergent protease, isolated from Bacillus licheniformis, was introduced in 1962. This enzyme, a particular type of protease called a subtilase, was stable at higher temperatures, had broad substrate specificity and worked well in alkaline conditions. The appearance of this enzyme and others similar to it (i.e., subtilisins) opened up the detergent enzymes market, and by 1969, 50% of the laundry detergent products sold in the United States and Europe contained enzymes. ... 

Subtilisin Carlsberg, a laundry enzyme, is extraordinarily cheap and stable even at extreme concentrations of substrate and salt at elevated temperature. A major disadvantage of this chemoenzymatic route was the fact that no racemization procedure for the unwanted (R)-enantiomer [(R)-3] could be established [40]. 

Protease is by far the most widely used of all detergent enzymes. Introduced in the 1960s, it has since become one of the more important components of detergent formulations [6]. Proteases aid in the removal of many soils commonly encountered by the consumer, such as food stains (cocoa, egg yolk, meat), blood, and grass. This enzyme hydrolyzes or breaks up the peptide bonds found in proteins resulting in the formation of smaller and more soluble polypeptides and amino acids. Since most enzymes have to function under high pH conditions, subtilisin, a bacterial alkaline protease, is commonly used in laundry detergents. This particular protease does not hydrolyze any specific peptide bond in proteinaceous stains but cleaves bonds in a somewhat random manner. 

ISynonyms/Trade Names Bacillus subtilis, Bacillus subtilis BPN, Bacillus subtilis Carlsburg, Proteolytic enzymes, I Subtilisin BPN, Subtilisin Carlsburg [Note Commercial proteolytic enzymes are used in laundry detergents.] ... 

The application of enzymes to organic synthesis is a small market, so most commercial enzymes are intended for other applications. For example, laundry detergents contain subtilisin to aid removal of food and blood stains. Commercial enzymes are sold by their properties that are not based on structure Many commercial enzymes are mixtures of pardy purified proteins and inert carriers. Table 5.2. Their composition is often proprietary, making it difficult to cormect properdes to specific stiucmres. 

Subtilisins subtilisin BL (Bacillus lentus), subtilisin BPN (S. amyloliquefaciens), subtilisin Carlsberg (S. licheniformis) Sigma-Aldrich, Dupont (Genencor), Novozymes Recombinant, many variants optimized for laundry and other cleaning applications... 

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