"Subtilisin" does not refer to a single protein, but to an entire clade under subtilases 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:
Other non-commercial names include ALK-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 include SP 266, orientase 10B (HBI Enzymes), Progress (Novozyme), Liquanase (Novozyme).
The active site features a charge-relay network involving Asp-32, His-64, and active site Ser-221 arranged in a catalytic 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's imidazole ring. This is possible because Asp is negatively charged at physiological pH. 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 the 3D structure to form the active site.
To summarize the interactions described above, Ser-221 acts as a nucleophile and cleaves peptide bonds with its partially negative oxygen atom. This is possible due to the nature of the charge-relay site of subtilisin.
Applications
Research tool
In molecular biology using B. subtilis as a model organism, the gene encoding subtilisin (aprE) is often the second gene of choice after amyE for integrating reporter constructs into, due to its dispensability.
Subtilisin can cause "enzymatic detergent asthma". People who are sensitive to Subtilisin (Alcalase) usually are also allergic to the bacterium Bacillus subtilis. [18]
^Markland FS, Smith EL (1971). "Subtilisins: primary structure, chemical and physical properties". In Boyer PD (ed.). The Enzymes. Vol. 3 (3rd ed.). New York: Academic Press. pp. 561–608.
^Nedkov P, Oberthür W, Braunitzer G (April 1985). "Determination of the complete amino-acid sequence of subtilisin DY and its comparison with the primary structures of the subtilisins BPN', Carlsberg and amylosacchariticus". Biological Chemistry Hoppe-Seyler. 366 (4): 421–30. doi:10.1515/bchm3.1985.366.1.421. PMID3927935.
^Polgár L (1987). "Structure and function of serine proteases". In Brocklehurst K, Neuberger A (eds.). Hydrolytic enzymes. Amsterdam: Elsevier. ISBN0-444-80886-8.
^Eschenburg, S; Genov, N; Peters, K; Fittkau, S; Stoeva, S; Wilson, KS; Betzel, C (15 October 1998). "Crystal structure of subtilisin DY, a random mutant of subtilisin Carlsberg". European Journal of Biochemistry. 257 (2): 309–18. doi:10.1046/j.1432-1327.1998.2570309.x. PMID9826175.
^Betzel, C; Klupsch, S; Branner, S; Wilson, KS (1996). Crystal structures of the alkaline proteases savinase and esperase from Bacillus lentus. Advances in Experimental Medicine and Biology. Vol. 379. pp. 49–61. doi:10.1007/978-1-4613-0319-0_7. ISBN978-0-306-45108-9. PMID8796310.
^Betzel, C; Klupsch, S; Papendorf, G; Hastrup, S; Branner, S; Wilson, KS (20 January 1992). "Crystal structure of the alkaline proteinase Savinase from Bacillus lentus at 1.4 A resolution". Journal of Molecular Biology. 223 (2): 427–45. doi:10.1016/0022-2836(92)90662-4. PMID1738156.
