IUBMB Enzyme Nomenclature


Accepted name: acyl-homoserine-lactone synthase

Reaction: an acyl-[acyl-carrier protein] + S-adenosyl-L-methionine = an [acyl-carrier protein] + S-methyl-5'-thioadenosine + an N-acyl-L-homoserine lactone

For diagram click here

Other name(s): acyl-homoserine lactone synthase; acyl homoserine lactone synthase; acyl-homoserinelactone synthase; acylhomoserine lactone synthase; AHL synthase; AHS; AHSL synthase; AhyI; AinS; AinS protein; autoinducer synthase; autoinducer synthesis protein rhlI; EsaI; ExpISCC1; ExpISCC3065; LasI; LasR; LuxI; LuxI protein; LuxM; N-acyl homoserine lactone synthase; RhlI; YspI

Systematic name: acyl-[acyl-carrier protein]:S-adenosyl-L-methionine acyltranserase (lactone-forming, methylthioadenosine-releasing)

Comments: Acyl-homoserine lactones (AHLs) are produced by a number of bacterial species and are used by them to regulate the expression of virulence genes in a process known as quorum-sensing. Each bacterial cell has a basal level of AHL and, once the population density reaches a critical level, it triggers AHL-signalling which, in turn, initiates the expression of particular virulence genes [5]. N-(3-Oxohexanoyl)-[acyl-carrier protein] and hexanoyl-[acyl-carrier protein] are the best substrates [1]. The fatty-acyl substrate is derived from fatty-acid biosynthesis through acyl-[acyl-carrier protein] rather than from fatty-acid degradation through acyl-CoA [1]. S-Adenosyl-L-methionine cannot be replaced by methionine, S-adenosylhomocysteine, homoserine or homoserine lactone [1].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


1. Schaefer, A.L., Val, D.L., Hanzelka, B.L., Cronan, J.E., Jr. and Greenberg, E.P. Generation of cell-to-cell signals in quorum sensing: acyl homoserine lactone synthase activity of a purified Vibrio fischeri LuxI protein. Proc. Natl. Acad. Sci. USA 93 (1996) 9505-9509. [PMID: 8790360]

2. Watson, W.T., Murphy, F.V., 4th, Gould, T.A., Jambeck, P., Val, D.L., Cronan, J.E., Jr., Beck von Bodman, S. and Churchill, M.E. Crystallization and rhenium MAD phasing of the acyl-homoserinelactone synthase EsaI. Acta Crystallogr. D Biol. Crystallogr. 57 (2001) 1945-1949. [PMID: 11717525]

3. Chakrabarti, S. and Sowdhamini, R. Functional sites and evolutionary connections of acylhomoserine lactone synthases. Protein Eng. 16 (2003) 271-278. [PMID: 12736370]

4. Hanzelka, B.L., Parsek, M.R., Val, D.L., Dunlap, P.V., Cronan, J.E., Jr. and Greenberg, E.P. Acylhomoserine lactone synthase activity of the Vibrio fischeri AinS protein. J. Bacteriol. 181 (1999) 5766-5770. [PMID: 10482519]

5. Parsek, M.R., Val, D.L., Hanzelka, B.L., Cronan, J.E., Jr. and Greenberg, E.P. Acyl homoserine-lactone quorum-sensing signal generation. Proc. Natl. Acad. Sci. USA 96 (1999) 4360-4365. [PMID: 10200267]

6. Ulrich, R.L. Quorum quenching: enzymatic disruption of N-acylhomoserine lactone-mediated bacterial communication in Burkholderia thailandensis. Appl. Environ. Microbiol. 70 (2004) 6173-6180. [PMID: 15466564]

7. Gould, T.A., Schweizer, H.P. and Churchill, M.E. Structure of the Pseudomonas aeruginosa acyl-homoserinelactone synthase LasI. Mol. Microbiol. 53 (2004) 1135-1146. [PMID: 15306017]

8. Raychaudhuri, A., Jerga, A. and Tipton, P.A. Chemical mechanism and substrate specificity of RhlI, an acylhomoserine lactone synthase from Pseudomonas aeruginosa. Biochemistry 44 (2005) 2974-2981. [PMID: 15723540]

9. Gould, T.A., Herman, J., Krank, J., Murphy, R.C. and Churchill, M.E. Specificity of acyl-homoserine lactone synthases examined by mass spectrometry. J. Bacteriol. 188 (2006) 773-783. [PMID: 16385066]

[EC created 2007]

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