摘要：Abstract Sialic acids comprise a family of terminal sugars essential for a variety of biological recognition systems. N-Propanoylmannosamine, an unphysiological sialic acid precursor, is taken up and metabolized by mammalian cells resulting in oligosaccharide-bound N-propanoylneuraminic acid. N-Propanoylmannosamine, applied to endogenously hyposialylated subclones of the myeloid leukemia HL60 and of the B-cell lymphoma BJA-B, both deficient in UDP-N-acetylglucosamine 2-epimerase, is efficiently metabolized to CMP-N-propanoylneuraminic acid resulting in up to 85% of glycoconjugate-associated sialic acids being unphysiological N-propanoylneuraminic acid. Thus, UDP-N-acetylglucosamine 2-epimerase-deficient cell lines provide an important experimental progress in engineering cells to display an almost homogeneous population of defined, structurally altered sialic acids.