The activation of homoserine through succinylation of homoserine in some bacteria, such as Escherichia coli and Bacillus cereus, is carried out by homoserine O-succinyltransferase (HTS, EC:2.3.1.46), while other bacteria, such as Haemophilus influenzae, Pseudomonas aeruginosa, and Mycobacterium tuberculosis, acetylate homoserine via homoserine O-acetyltransferase (HTA;EC:2.3.1.31) [1,2]. This family also includes serine acetyltransferase CysE (EC:2.3.1.30) from Lactobacillus casei, which catalyses the formation of O-acetyl serine from L-serine and acetyl-CoA, and is involved in cysteine biosynthesis [3].

1: Assessing the roles of essential functional groups in the mechanism of homoserine succinyltransferase. Coe DM, Viola RE; Arch Biochem Biophys. 2007;461:211-218. PMID:17442255

2: Crystal structure of homoserine O-succinyltransferase from Bacillus cereus at 2.4 A resolution. Zubieta C, Krishna SS, McMullan D, Miller MD, Abdubek P, Agarwalla S, Ambing E, Astakhova T, Axelrod HL, Carlton D, Chiu HJ, Clayton T, Deller M, DiDonato M, Duan L, Elsliger MA, Grzechnik SK, Hale J, Hampton E, Han GW, Haugen J, Jaroszewski L, Jin KK, Klock HE, Knuth MW, Koesema E, Kumar A, Marciano D, Morse AT, Nigoghossian E, Oommachen S, Reyes R, Rife CL, van den Bedem H, Weekes D, White A, Xu Q, Hodgson KO, Wooley J, Deacon AM, Godzik A, Lesley SA, Wilson IA; Proteins. 2007;68:999-1005. PMID:17546672

3: Cysteine biosynthesis in Lactobacillus casei: identification and characterization of a serine acetyltransferase. Bogicevic B, Berthoud H, Portmann R, Bavan T, Meile L, Irmler S; FEMS Microbiol Lett. 2016; [Epub ahead of print] PMID:26790714