N-alpha-acetyltransferase that acetylates the amino terminal acidic residue of proteins devoid of initiator methionine (PubMed:29581307). Preferentially acts on proteins starting with Asp-Asp-Asp and Glu-Glu-Glu sequences (PubMed:29581307). In vitro, shows high activity towards N-terminal sequences starting with Met-Asp-Glu-Leu, Met-Glu-Glu-Glu and Met-Asp-Asp-Asp (PubMed:29581307). acetyl-CoA + N-terminal L-aspartyl-L-aspartyl-L-aspartyl-[protein] = CoA + H(+) + N-terminal N-acetyl-L-aspartyl-L-aspartyl-L-aspartyl-[protein] acetyl-CoA + N-terminal L-glutamyl-L-glutamyl-L-glutamyl-[protein] = CoA + H(+) + N-terminal N-acetyl-L-glutamyl-L-glutamyl-L-glutamyl-[protein] kcat is 0.6 min(-1) for Asp-Asp-Asp-Ile peptide (PubMed:29581307). kcat is 0.6 min(-1) for Glu-Glu-Glu-Ile peptide (PubMed:29581307). kcat is 3.47 min(-1) for Met-Asp-Asp-Asp peptide (PubMed:29581307). kcat is 3.45 min(-1) for Met-Glu-Glu-Glu peptide (PubMed:29581307). kcat is 16.86 min(-1) for Met-Asp-Glu-Leu peptide (PubMed:29581307). Belongs to the acetyltransferase family.