Lysophosphatidic acid acyltransferase [“LPAAT”] participates in the second step of oil biosynthesis and is expected to play a key role in altering the quantity of long-chain polyunsaturated fatty acids [“LC-PUFAs”] produced in oils of oleaginous organisms. An LPAAT isolated from Mortierella alpina [“MaLPAAT1”] that is suitable for use in the manufacture of oils enriched in LC-PUFAs in oleaginous organisms is disclosed. Most desirably, the substrate specificity of the instant MaLPAAT1 will be particularly useful to enable increased C18 to C20 elongation conversion efficiency and increased Δ4 desaturation conversion efficiency in recombinant host cells producing LC-PUFAs.