N-alpha protein acetylation, catalyzed by N-alpha acetyltransferase complex, is a common protein -modification process in eukaryotic cells. Despite its widespread occurrence, the biological significance of this modification process is still unclear. We recently discovered a novel testis-predominant isoform of the catalytic subunit of the enzyme complex. Here, we describe the biochemical characterization of this testis-predominant N-alpha acetyltransferase complex, which includes protein-protein interaction study by co-immunoprecipitation experiment and functional study by N-alpha acetyltransferase assay.