The function of ENSG00000121579 (NAA50, N-alpha-acetyltransferase 50, NatE catalytic subunit) is as follows. N-alpha-acetyltransferase that acetylates the N-terminus of proteins that retain their initiating methionine (PubMed:19744929, PubMed:21900231, PubMed:22311970, PubMed:27484799). Has a broad substrate specificity: able to acetylate the initiator methionine of most peptides, except for those with a proline in second position (PubMed:27484799). Also displays N-epsilon-acetyltransferase activity by mediating acetylation of the side chain of specific lysines on proteins (PubMed:19744929). Autoacetylates in vivo (PubMed:19744929). The relevance of N-epsilon-acetyltransferase activity is however unclear: able to acetylate H4 in vitro, but this result has not been confirmed in vivo (PubMed:19744929). Component of N-alpha- acetyltransferase complexes containing NAA10 and NAA15, which has N- alpha-acetyltransferase activity (PubMed:16507339, PubMed:27484799, PubMed:29754825, PubMed:32042062). Does not influence the acetyltransferase activity of NAA10 (PubMed:16507339, PubMed:27484799). However, it negatively regulates the N-alpha-acetyltransferase activity of the N-terminal acetyltransferase A complex (also called the NatA complex) (PubMed:32042062). The multiprotein complexes probably constitute the major contributor for N-terminal acetylation at the ribosome exit tunnel, with NAA10 acetylating all amino termini that are devoid of methionine and NAA50 acetylating other peptides (PubMed:16507339, PubMed:27484799). Required for sister chromatid cohesion during mitosis by promoting binding of CDCA5/sororin to cohesin: may act by counteracting the function of NAA10 (PubMed:17502424, PubMed:27422821). {ECO:0000269|PubMed:16507339, ECO:0000269|PubMed:17502424, ECO:0000269|PubMed:19744929, ECO:0000269|PubMed:21900231, ECO:0000269|PubMed:22311970, ECO:0000269|PubMed:27422821, ECO:0000269|PubMed:27484799, ECO:0000269|PubMed:29754825, ECO:0000269|PubMed:32042062}.