Supports initiation of fatty acid biosynthesis in the absence of FabH. Lipid metabolism; fatty acid biosynthesis. In the absence of FabH, expression is positively regulated by the stringent response factors (p)ppGpp and DksA. Deletion mutant does not exhibit any growth defect. Combined inactivation of FabH and FabY results in growth arrest, possibly due to the loss of fatty acid biosynthesis. Overexpression rescues altered fatty acid profile, growth defect and reduced cell size of the fabH deletion mutant. Belongs to the acetyltransferase family. FabY subfamily.