| Peptidase S8, subtilisin-related | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 | |||||||||
| Identifiers | |||||||||
| Symbol | Peptidase_S8 | ||||||||
| Pfam | PF00082 | ||||||||
| InterPro | IPR015500 | ||||||||
| PROSITE | PDOC00125 | ||||||||
| CATH | 1cse | ||||||||
| SCOP2 | 1cse /SCOPe /SUPFAM | ||||||||
| CDD | cd07477 | ||||||||
| |||||||||
| Subtilisin BPN' | |||||||
|---|---|---|---|---|---|---|---|
 Crystal structure of subtilisin S8 domain.[1] | |||||||
| Identifiers | |||||||
| Organism | Bacillus amyloliquefaciens | ||||||
| Symbol | apr | ||||||
| CAS number | 9014-01-1 | ||||||
| Entrez | 5712479 | ||||||
| PDB | 1st2More structures | ||||||
| UniProt | P00782 | ||||||
| Other data | |||||||
| EC number | 3.4.21.62 | ||||||
| |||||||
| GO:0004252 | |||||||
Subtilisin is aprotease (aprotein-digestingenzyme) initially obtained fromBacillus subtilis.[2][3][4][5][6][7][8]
Subtilisins belong tosubtilases, a group ofserine proteases that – like all serine proteases – initiate thenucleophilic attack on thepeptide (amide) bond through a serineresidue at theactive site. Subtilisins typically have molecular weights 27kDa. They can be obtained from certain types ofsoilbacteria, for example,Bacillus amyloliquefaciens from which they are secreted in large amounts.
"Subtilisin" does not refer to a single protein, but to an entireclade undersubtilases containing the classical subtilisins. The clade can be further divided into four groups: "true subtilisins" (containing the classical members), "high-alkaline subtilisins", "intracellular subtilisins", and "phylogenetically intermediate subtilisins" (PIS).[9][10] Notable subtilisins include:
| Family | Organism | Uniprot | Names | Notes |
|---|---|---|---|---|
| True | B. licheniformis | P00780 | Subtilisin Carlsberg,Alcalase (Novozymes),Maxatase (?) "subtilisin DY" (X-ray mutant)[11] | Typeserine endopeptidase of MEROPS family S8. |
| ? | B. licheniformis | ? | Endocut-02L (Tailorzyme ApS) | |
| ? | ? | ? | bioprase,bioprase AL | |
| ? | Lederbergia lenta | Esperase (Novozymes) | Structure determined, but not found on PDB.[12] | |
| High-alkaline | Lederbergia lenta | P29600 | Subtilisin Savinase,Savinase (Novozymes) | PDB:1SVN[13] |
| True | B. amyloliquefaciens | P00782 | Subtilisin BPN’,Alcalase (Novozymes) | |
| ? | Geobacillus stearothermophilus | P29142 | Subtilisin J,Thermoase (Amano) | [14] |
Other non-commercial names includeALK-enzyme,bacillopeptidase,Bacillus subtilis alkaline proteinase,colistinase,genenase I,protease XXVII,subtilopeptidase,kazusase,protease VIII,protin A 3L,protease S.
Other commercial names with unidentified molecular identities includeSP 266,orientase 10B (HBI Enzymes),Progress (Novozyme),Liquanase (Novozyme).
The structure of subtilisin has been determined byX-ray crystallography. The mature form is a 275-residueglobular protein with severalalpha-helices, and a largebeta-sheet. The N-terminal contains an I9 propeptide domain (InterPro: IPR010259) that assists the folding of subtilisin. Proteolytic removal of the domain activates the enzyme. It is structurally unrelated to thechymotrypsin-clan of serine proteases, but uses the same type ofcatalytic triad in theactive site. This makes it a classic example ofconvergent evolution.
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The active site features a charge-relay network involving Asp-32, His-64, and active site Ser-221 arranged in acatalytic triad. The charge-relay network functions as follows: The carboxylate side-chain of Asp-32 hydrogen-bonds to a nitrogen-bonded proton on His-64'simidazole ring. This is possible because Asp is negatively charged at physiologicalpH. The other nitrogen on His-64 hydrogen-bonds to the O-H proton of Ser-221. This last interaction results in charge-separation of O-H, with the oxygen atom being more nucleophilic. This allows the oxygen atom of Ser-221 to attack incoming substrates (i.e., peptide bonds), assisted by a neighboring carboxyamide side-chain of Asn-155.
Even though Asp-32, His-64, and Ser-221 are sequentially far apart, they converge in the3D structure to form the active site.
To summarize the interactions described above, Ser-221 acts as anucleophile and cleavespeptide bonds with its partially negative oxygen atom. This is possible due to the nature of the charge-relay site of subtilisin.
In molecular biology usingB. subtilis as amodel organism, the gene encoding subtilisin (aprE) is often the second gene of choice afteramyE for integrating reporter constructs into, due to its dispensability.
Protein-engineered subtilisins are widely used in commercial products (the native enzyme is easily inactivated by detergents and high temperatures) and is also called a stain cutter, for example, in laundry[15] and dishwashingdetergents,cosmetics,food processing,[16] skin care products,contact lens cleaners, and for research insynthetic organic chemistry.
People can be exposed to subtilisin in the workplace by breathing it in, swallowing it, skin contact, and eye contact. TheNational Institute for Occupational Safety and Health (NIOSH) has set arecommended exposure limit (REL) of 60 ng/m3 over a 60-minute period.[17]
Subtilisin can cause "enzymatic detergent asthma". People who are sensitive to Subtilisin (Alcalase) usually are also allergic to the bacteriumBacillus subtilis.[18]
