(Citrate-synthase)-lysyl-methyltransferase (CSKMT, METTL12) transfers three methyl groups from S-adenosylmethionine (SAM) to lysine-395 of citrate synthase (CS). The expression of CSKMT is low or absent in many normal organ tissues, but the trimethylated form is predominant in most cell lines tested. The modification is evolutionarily conserved, with contradicting reports on the activity of modified CS, while the effect on the whole CS/ACO2 metabolon was not investigated. Oxalocetate inhibits methyltransferase activity (Malecki et al., 2017; Rhein et al., 2017; reviewed in Qi et al., 2023).