CHEMICAL SYNTHESIS OF LUOROMETHYLUMBELLIFERYL-ALPHA-D-N-ACETYLNEURAMINIC ACID GLYCOSIDE AND ITS USE FOR THE FLUOROMETRIC DETECTION OF POORLY EXPRESSED NATURAL AND RECOMBINANT SIALIDASES

When compared to bacterial or viral sialidases, eukaryotic sialidases are expressed at lower levels and frequently show poor specific activi ties. The identification and characterization of sialidases from eukar yotes have been slowed down due to the limited sensitivity of availabl e sialidase substrates. Therefore, ive chemically synthesized a fluoro genic compound, luoromethylumbelliferyl-alpha-D-N-acetylneuraminic aci d (CF3MU-Neu5Ac), and tested its use as a substrate for eight differen t sialidases, including enzymes from viral, bacterial, and eukaryotic sources. Kinetic analysis revealed CF3MU-Neu5Ac to be a very sensitive sialidase substrate. Furthermore, this substance proves to be perfect ly suitable for the in vivo examination of sialidases and for the dete ction of recombinant sialidase by means of expression cloning. (C) 199 7 Academic Press.