Histone acetyltransferase localized in the Golgi apparatus that mediates acetylation of free histone H4, thereby facilitating nucleosome assembly. Has a preference for free histone H4 'Lys-20'(H4K20ac), 'Lys-79'(H4K79ac) and 'Lys-91' (H4K91ac). Also displays alpha (N-terminal) acetyltransferase activity towards a range of N-terminal sequences including those starting with Met-Lys, Met-Val, Met-Ala and Met-Met. Required for normal chromosomal segregation during anaphase.