N-alpha-acetyltransferase that specifically mediates the acetylation of the N-terminal residues of histones H4 and H2A. In contrast to other N-alpha-acetyltransferase, has a very specific selectivity for histones H4 and H2A N-terminus and specifically recognizes the 'Ser-Gly-Arg-Gly sequence'. Acts as a negative regulator of apoptosis. May play a role in hepatic lipid metabolism (By similarity.,NAA40,NAT11,NatD,PATT1,hNatD,Epigenetics & Nuclear Signaling,Cancer,Invasion and Metastasis,Cell Biology & Developmental Biology,Apoptosis,NAA40