Catalyzes the condensation of L-serine with palmitoyl-CoA (hexadecanoyl-CoA) to produce 3-oxosphinganine (PubMed:17557831). Exhibits a broad substrate specificity concerning the chain length and the degree of unsaturation of acyl-CoA (PubMed:17557831). H(+) + hexadecanoyl-CoA + L-serine = 3-oxosphinganine + CO2 + CoA kcat is 0.12 sec(-1). Optimum pH is 7.4 to 8.0. Lipid metabolism; sphingolipid metabolism. Homodimer. Distributed mainly near the inner membrane of the cell. Belongs to the class-II pyridoxal-phosphate-dependent aminotransferase family.