The function of Ensembl gene identifier ENSG00000139624 (CERS5, ceramide synthase 5) is as follows. Ceramide synthase that catalyzes the transfer of the fatty acyl chain from fatty acyl-CoA to a sphingoid base, with high selectivity toward palmitoyl-CoA (hexadecanoyl-CoA; C16:0-CoA) (PubMed:16951403, PubMed:18541923, PubMed:22144673, PubMed:22661289, PubMed:23530041, PubMed:26887952, PubMed:29632068, PubMed:31916624). Can use different sphingoid bases as substrates for ceramide synthesis, such as sphinganine in de novo synthesis, and sphing-4E-enine (sphingosine), (4R)-hydroxysphinganine (phytosphingosine) or sphinga- 4E,14Z-dienine in salvage pathways (PubMed:31916624). Other fatty acyl- CoAs such as long-chain saturated stearoyl-CoA (octadecanoyl-CoA; C18:0-CoA), myristoyl-CoA (tetradecanoyl-CoA; C14:0-CoA), and monounsaturated oleoyl-CoA (9Z-octadecenoyl-CoA; C18:1-CoA) can also act as acyl donors, but with less efficiency than hexadecanoyl-CoA (By similarity). Plays a role in de novo ceramide synthesis and surfactant homeostasis in pulmonary epithelia (By similarity). {ECO:0000250|UniProtKB:Q9D6K9, ECO:0000269|PubMed:16951403, ECO:0000269|PubMed:18541923, ECO:0000269|PubMed:22144673, ECO:0000269|PubMed:22661289, ECO:0000269|PubMed:23530041, ECO:0000269|PubMed:26887952, ECO:0000269|PubMed:29632068, ECO:0000269|PubMed:31916624}.